Text Encoding Initiative
The XML Version of the TEI Guidelines
23 Language Corpora
The term language corpus is used to mean a number of rather different things. It may refer simply to any collection of linguistic data (written, spoken, or a mixture of the two), although many practitioners prefer to reserve it for collections which have been organized or collected with a particular end in view, generally to characterize a particular state or variety of one or more languages. Because opinions as to the best method of achieving this goal differ, various subcategories of corpora have also been identified. For our purposes however, the distinguishing characteristic of a corpus is that its components have been selected or structured according to some conscious set of design criteria.
These design criteria may be very simple and undemanding, or very sophisticated. A corpus may be intended to represent (in the statistical sense) a particular linguistic variety or sublanguage, or it may be intended to represent all aspects of some assumed `core' language. A corpus may be made up of whole texts or of fragments or text samples. It may be a `closed' corpus, or an `open' or `monitor' corpus, the composition of which may change over time. However, since an open corpus is of necessity finite at any particular point in time, the only likely effect of its expansibility from the encoding point of view may be some increased difficulty in maintaining consistent encoding practices (see further section 23.5 Recommendations for the Encoding of Large Corpora). For simplicity, therefore, our discussion largely concerns ways of encoding closed corpora, regarded as single but composite texts.
Language corpora are regarded by these Guidelines as composite texts rather than unitary texts (on this distinction, see chapter 7 Default Text Structure). This is because although each discrete sample of language in a corpus clearly has a claim to be considered as a text in its own right, it is also regarded as a subdivision of some larger object, if only for convenience of analysis. Corpora share a number of characteristics with other types of composite texts, including anthologies and collections. Most notably, different components of composite texts may exhibit different structural properties (for example, some may be composed of verse, and others of prose), thus potentially requiring elements from different TEI bases. Composite texts are thus especially likely to require the techniques for combining base tag sets described in section 3.4 Combining TEI Base Tag Sets.
Aside from these high-level structural differences, and possibly differences of scale, the encoding of language corpora and the encoding of individual texts present identical sets of problems. Any of the encoding techniques and elements presented in other chapters of these Guidelines may therefore prove relevant to some aspect of corpus encoding and may be used in corpora. However, we do not repeat here the discusssion of such fundamental matters as the representation of multiple character sets (see chapter 4 Languages and Character Sets); nor attempt to summarize the variety of elements provided for encoding basic structural features such as quoted or highlighted phrases, cross references, lists, notes, editorial changes and reference systems (see chapter 6 Elements Available in All TEI Documents). In addition to these general purpose elements, these Guidelines offer a range of more specialized sets of tags which may be of use in certain specialized corpora, for example those consisting primarily of verse (chapter 9 Base Tag Set for Verse), drama (chapter 10 Base Tag Set for Drama), transcriptions of spoken text (chapter 11 Transcriptions of Speech), etc. Chapter 3 Structure of the TEI Document Type Definition should be reviewed for details of how these and other components of the Guidelines should be tailored to create a document type definition appropriate to a given application. In sum, it should not be asssumed that only the matters specifically addressed in this chapter are of importance for corpus creators.
This chapter does however include some other material relevant to corpora and corpus-building, for which no other location appeared suitable. It begins with a review of the distinction between unitary and composite texts, and of the different methods provided by these Guidelines for representing composite texts of different kinds (section 23.1 Varieties of Composite Text). Section 23.2 Contextual Information describes a set of additional header elements provided for the documentation of contextual information, of importance largely though not exclusively to language corpora. This is the additional tag set for language corpora proper. Section 23.3 Associating Contextual Information with a Text discusses a mechanism by which individual parts of the TEI Header may be associated with different parts of a TEI-conformant text. Section 23.4 Linguistic Annotation of Corpora reviews various methods of providing linguistic annotation in corpora, with some specific examples of relevance to current practice in corpus linguistics. Finally, section 23.5 Recommendations for the Encoding of Large Corpora provides some general recommendations about the use of these Guidelines in the building of large corpora.
In these Guidelines, the word text refers to any stretch of discourse, whether complete or incomplete, unitary or composite, which the encoder chooses (perhaps merely for purposes of analytic convenience) to regard as a unit. The term composite text refers to texts within which other texts appear; the following common cases may be distinguished:
The tags listed above may be combined to encode each of these varieties of composite text in different ways.
In corpora, the component samples are clearly distinct texts, but the systematic collection, standardized preparation, and common markup of the corpus often make it useful to treat the entire corpus as a unit, too. Some corpora may become so well established as to be regarded as texts in their own right; the Brown and LOB corpora are now close to achieving this status.
The <teiCorpus.2> element is intended for the encoding of language corpora, though it may also be useful in encoding newspapers, electronic anthologies, and other disparate collections of material. The individual samples in the corpus are encoded as separate <TEI.2> elements, and the entire corpus is enclosed in a <teiCorpus.2> element. Each sample has the usual structure for a <TEI.2> document, comprising a <teiHeader> followed by a <text> element. The corpus, too, has a corpus-level <teiHeader> element, in which the corpus as a whole, and encoding practices common to multiple samples may be described. The overall structure of a TEI-conformant corpus is thus:
<teiCorpus.2> <teiHeader type='corpus'> <!-- TEI header for corpus-level information --> </teiHeader> <TEI.2 id='T1'> <teiHeader type='text'> <!-- ... --> </teiHeader> <text> <!-- ... --> </text> </TEI.2> <TEI.2 id='T2'> <teiHeader type='text'> <!-- ... --> </teiHeader> <text> <!-- ... --> </text> </TEI.2> <!-- ... etc. --> </teiCorpus.2>
Header information which relates to the whole corpus rather than to individual components of it should be factored out and included in the <teiHeader> element prefixed to the whole. This two-level structure allows for contextual information to be specified at the corpus level, at the individual text level, or at both. Discussion of the kinds of information which may thus be specified is provided below, in section 23.2 Contextual Information, as well as in chapter 5 The TEI Header. Information of this type should in general be specified only once: a variety of methods are provided for associating it with individual components of a corpus, as further described in section 23.3 Associating Contextual Information with a Text.
In some cases, the design of a corpus is reflected in its internal structure. For example, a corpus of newspaper extracts might be arranged to combine all stories of one type (reportage, editorial, reviews, etc.) into some higher-level grouping, possibly with sub-groups for date, region, etc. The <teiCorpus.2> element provides no direct support for reflecting such internal corpus structure in the markup: it treats the corpus as an undifferentiated series of components, each tagged <TEI.2>.
If it is essential to reflect a single permanent organization of a corpus into sub- and sub-sub-corpora, then the corpus or the high-level subcorpora may be encoded as composite texts, using the <group> element described below and in section 7.3 Groups of Texts. The mechanisms for corpus characterization described in this chapter, however, are designed to reduce the need to do this. Useful groupings of components may easily be expressed using the text classification and identification elements described in section 23.2.1 The Text Description, and those for associating declarations with corpus components described in section 23.3 Associating Contextual Information with a Text. These methods also allow several different methods of text grouping to co-exist, each to be used as needed at different times. This helps minimize the danger of cross-classification and mis-classification of samples, and helps improve the flexibility with which parts of a corpus may be characterized for different applications.
Anthologies and collections are often treated as texts in their own right, if only for historical reasons. In conventional publishing, at least, anthologies are published as units, with single editorial responsibility and common front and back matter which may need to be included in their electronic encodings. The texts collected in the anthology, of course, may also need to identifiable as distinct individual objects for study.
Poem cycles, epistolary novels, and epistolary essays differ from anthologies in that they are often written as single works, by single authors, for single occasions; nevertheless, it can be useful to treat their constituent parts as individual texts, as well as the cycle itself. Structurally, therefore, they may be treated in the same way as anthologies: in both cases, the body of the text is composed largely of other texts.
The <group> element is provided to simplify the encoding of collections, anthologies, and cyclic works; as noted above, the <group> element can also be used to record the potentially complex internal structure of language corpora. For full description, see chapter 7 Default Text Structure.
Some composite texts, finally, are neither corpora, nor anthologies, nor cyclic works: they are otherwise unitary texts within which other texts are embedded. In general, they may be treated in the same way as unitary texts, using the normal <TEI.2> and <body> elements. The embedded text itself may be encoded using the <text> element, which may occur within quotations or between paragraphs or other chunk-level elements inside the sections of a larger text. For further discussion, see chapter 7 Default Text Structure.
All composite texts share the characteristic that their different component texts may be of structurally similar or dissimilar types. If all component texts may all be encoded using the same base tag set, then no problem arises. If however they require different base tag sets, then either the general or the mixed base tag set must be used, in addition to all relevant base tag sets. This process is described in more detail in section 3.4 Combining TEI Base Tag Sets.
Contextual information is of particular importance for collections or corpora composed of samples from a variety of different kinds of text. Examples of such contextual information include: the age, sex and geographical origins of participants in a language interaction, or their socio-economic status; the cost and publication data of a newspaper; the topic, register or factuality of an extract from a textbook. Such information may be of the first importance, whether as an organizing principle in creating a corpus (for example, to ensure that the range of values in such a parameter is evenly represented throughout the corpus, or represented proportionately to the population being sampled), or as a selection criterion in analysing the corpus (for example, to investigate the language usage of some particular vector of social characteristics).
Such contextual information is potentially of equal importance for unitary texts, and these Guidelines accordingly make no particular distinction between the kinds of information which should be gathered for unitary and for composite texts. In either case, the information should be recorded in the appropriate section of a TEI Header, as described in chapter 5 The TEI Header. In the case of language corpora, such information may be gathered together in the overall corpus header, or split across all the component texts of a corpus, in their individual headers, or divided between the two. The association between an individual corpus text and the contextual information applicable to it may be made in a number of ways, as further discussed in section 23.3 Associating Contextual Information with a Text below.
Chapter 5 The TEI Header, which should be read in conjunction with the present section, describes in full the range of elements available for the encoding of information relating to the electronic file itself, for example its bibliographic description and those of the source or sources from which it was derived (see section 5.2 The File Description); information about the encoding practices followed with the corpus, for example its design principles, editorial practices, reference system etc. (see section 5.3 The Encoding Description); more detailed descriptive information about the creation and content of the corpus, such as the languages used within it and any descriptive classification system used (see section 5.4 The Profile Description); and version information documenting any changes made in the electronic text (see section 5.5 The Revision Description).
In addition to the elements defined by chapter 5 The TEI Header, several other elements can be used in the TEI header if the additional tag set defined by this chapter is invoked. These additional tags make it possible to characterize the social or other situation within which a language interaction takes place or is experienced, the physical setting of a language interaction, and the participants in it. Though this information may be relevant to, and provided for, unitary texts as well as for collections or corpora, it is more often recorded for the components of systematically developed corpora than for isolated texts, and thus the additional tag set is referred to as being ‘for language corpora’. Included in this tag set are the following elements:
<!-- 23.2: Header extensions for Corpus Texts--> <!ELEMENT textDesc %om.RO; ( channel, constitution, derivation, domain, factuality, interaction, preparedness, purpose+ ) > <!ATTLIST textDesc %a.global; %a.declarable; TEIform CDATA 'textDesc' > <!ELEMENT particDesc %om.RO; ( p+ | ( (person | personGrp)+, particLinks? ) ) > <!ATTLIST particDesc %a.global; %a.declarable; TEIform CDATA 'particDesc' > <!ELEMENT settingDesc %om.RO; (p+ | setting+)> <!ATTLIST settingDesc %a.global; %a.declarable; TEIform CDATA 'settingDesc' > [continued in 23.2: Text description] [continued in 23.2: Participants description] [continued in 23.2: Setting description] <!-- end of 23.2-->
The additional tag set for language corpora will be invoked, thus enabling the use of these elements, if a parameter entity called TEI.corpus is declared with the value INCLUDE, somewhere within the DTD subset. If the document is structured as a TEI corpus (that is, using the <teiCorpus.2> element), its document type declaration will resemble this:
<!DOCTYPE teiCorpus.2 PUBLIC "-//TEI P4//DTD Main Document Type//EN" "tei2.dtd" [ <!ENTITY % TEI.XML 'INCLUDE' > <!ENTITY % TEI.corpus 'INCLUDE' > ]>
The <textDesc> element provides a full description of the situation within which a text was produced or experienced, and thus characterizes it in a way relatively independent of any a priori theory of text-types. It is provided as an alternative or a supplement to the common use of descriptive taxonomies used to categorize texts, which is fully described in section 5.4.3 The Text Classification, and section 5.3.6 The Classification Declaration. The description is organized as a set of values and optional prose descriptions for the following eight situational parameters, each represented by one of the following eight elements:
A TEI-conformant text description contains each of the above elements, supplied in the order specified. Except for the <purpose> element, which may be repeated to indicate multiple purposes, no element may appear more than once within a single text description. Each element may be empty, or may contain a brief qualification or more detailed description of the value expressed by its attributes. It should be noted that some texts, in particular literary ones, may resist unambiguous classification in some of these dimensions; in such cases, the situational parameter in question should be given the content ‘not applicable’ or an equivalent phrase.
Texts may be described along many dimensions, according to many different taxonomies. No generally accepted consensus as to how such taxonomies should be defined has yet emerged, despite the best efforts of many corpus linguists, text linguists, sociolinguists, rhetoricians, and literary theorists over the years. Rather than attempting the task of proposing a single taxonomy of text-types (or the equally impossible one of enumerating all those which have been proposed previously), the closed set of situational parameters described above can be used in combination to supply useful distinguishing descriptive features of individual texts, without insisting on a system of discrete high-level text-types. Such text-types may however be used in combination with the parameters proposed here, with the advantage that the internal structure of each such text-type can be specified in terms of the parameters proposed. This approach has the following analytical advantages:163
Two alternative approaches to the use of these parameters are supported by these Guidelines. One is to use pre-existing taxonomies such as those used in subject classification or other types of text categorization. Such taxonomies may also be appropriate for the description of the topics addressed by particular texts. Elements for this purpose are described in section 5.4.3 The Text Classification, and elements for defining or declaring such classification schemes in section 5.3.6 The Classification Declaration. A second approach is to develop an application-specific set of feature structures and an associated feature system declaration, as described in chapters 16 Feature Structures and 26 Feature System Declaration.
Where the organizing principles of a corpus or collection so permit, it may be convenient to regard a particular set of values for the situational parameters listed in this section as forming a text-type in its own right; this may also be useful where the same set of values applies to several texts within a corpus. In such a case, the set of text-types so defined should be regarded as a taxonomy. The mechanisms described in section 5.3.6 The Classification Declaration may be used to define hierarchic taxonomies of such text-types, provided that the <catDesc> component of the <category> element contains a <textDesc> element rather than a prose description. Particular texts may then be associated with such definitions using the mechanisms described in sections 5.4.3 The Text Classification.
<textDesc id="t1" n="Informal domestic conversation"> <channel mode="s">informal face-to-face conversation</channel> <constitution type="single">each text represents a continuously recorded interaction among the specified participants </constitution> <derivation type="original"> </derivation> <domain type="domestic">plans for coming week, local affairs</domain> <factuality type="mixed">mostly factual, some jokes</factuality> <interaction type="complete" active="plural" passive="many"> </interaction> <preparedness type="spontaneous"> </preparedness> <purpose type="entertain" degree="high"> </purpose> <purpose type="inform" degree="medium"> </purpose> </textDesc>
<textDesc n="novel"> <channel mode="w">print; part issues</channel> <constitution type="single"> </constitution> <derivation type="original"> </derivation> <domain type="art"> </domain> <factuality type="fiction"> </factuality> <interaction type="none"> </interaction> <preparedness type="prepared"> </preparedness> <purpose type="entertain" degree="high"> </purpose> <purpose type="inform" degree="medium"> </purpose> </textDesc>The formal declarations for these elements are given below:
<!-- 23.2.1: Text description--> <!ELEMENT channel %om.RO; %phrase.seq;> <!ATTLIST channel %a.global; mode (s | w | ws | sw | m | x) "x" TEIform CDATA 'channel' > <!ELEMENT constitution %om.RO; %phrase.seq;> <!ATTLIST constitution %a.global; type (single | composite | frags | unknown) "single" TEIform CDATA 'constitution' > <!ELEMENT derivation %om.RO; %phrase.seq;> <!ATTLIST derivation %a.global; type CDATA #IMPLIED TEIform CDATA 'derivation' > <!ELEMENT domain %om.RO; %phrase.seq;> <!ATTLIST domain %a.global; type CDATA #IMPLIED TEIform CDATA 'domain' > <!ELEMENT factuality %om.RO; %phrase.seq;> <!ATTLIST factuality %a.global; type (fiction|fact|mixed|inapplicable) #IMPLIED TEIform CDATA 'factuality' > <!ELEMENT interaction %om.RO; %phrase.seq;> <!ATTLIST interaction %a.global; type (none|partial|complete|inapplicable) #IMPLIED active CDATA #IMPLIED passive CDATA #IMPLIED TEIform CDATA 'interaction' > <!ELEMENT preparedness %om.RO; %phrase.seq;> <!ATTLIST preparedness %a.global; type CDATA #IMPLIED TEIform CDATA 'preparedness' > <!ELEMENT purpose %om.RO; %phrase.seq;> <!ATTLIST purpose %a.global; type CDATA #IMPLIED degree (high | medium | low | unknown) #IMPLIED TEIform CDATA 'purpose' > <!-- end of 23.2.1-->
The <particDesc> element in the <profileDesc> element provides additional information about the participants in a spoken text or, where this is judged appropriate, the persons named or depicted in a written text. Individual speakers or groups of speakers may be named or identified by a code which can then be used elsewhere within the encoded text, for example as the value of a who attribute. Demographic and descriptive information may be supplied about their individual characteristics and the relationships between them.
It should be noted that although the terms speaker or participant are used throughout this section, it is intended that the same mechanisms may be used to characterize fictional personŠ or `voices' within a written text, except where otherwise stated. For the purposes of analysis of language usage, the information specified here should be equally applicable to written and spoken texts.
Both <person> and <personGrp> elements have the same substructure. This may be a prose description, or, more formally, a series of specialized subelements providing more specific details. Such details will vary enormously for different kinds of analysis; the set of demographic characteristics presented here as sub-elements should therefore be regarded as providing only an indication of the kinds of descriptive information which have been found to be generally useful, for example in socio-linguistics. Users of these Guidelines are free to extend or modify this set of demographic characteristics, by redefining the parameter entity m.demographics, associated with the class demographics, as further described in chapter 29 Modifying and Customizing the TEI DTD. Where well-known classification schemes exist, e.g. for socio-economic class or occupation, these should be used and may be documented in the same way as for text classification (see section 5.3.6 The Classification Declaration)
<person id="p1" sex="f" age="mid"> <p>Female informant, well-educated, born in Shropshire UK, 12 Jan 1950, of unknown occupation. Speaks French fluently. Socio-Economic status B2 in the PEP classification scheme.</p> </person>Provided that the ‘PEP classification scheme’ has been defined elsewhere in the heading (as a <taxonomy> element within the <textClass> element; see 5.3.6 The Classification Declaration), the same individual might more formally be described as follows:
<person id="p1" sex="f" age="mid"> <birth date="1950-01-12"> <date>12 Jan 1950</date> <name type="place">Shropshire, UK</name> </birth> <firstLang>English</firstLang> <langKnown>French</langKnown> <residence>Long term resident of Hull</residence> <education>University postgraduate</education> <occupation>Unknown</occupation> <socecStatus scheme="pep" code="b2"/> </person>
Dates and names of persons or places, if included in the prose description, may be encoded using either the general purpose <date>, <name> or <rs> elements discussed in section 6.4 Names, Numbers, Dates, Abbreviations, and Addresses, or the more specialised and detailed elements provided by chapter 20 Names and Dates. In the latter case, the additional tag set for names and dates must be enabled together with that for language corpora.
An identified character in a drama or a novel might be defined using a subset of the same tags as follows:164
<person id="em01" sex="f" age="young"> <p><name>Emma Woodhouse</name></p> </person>
As noted above, the <particLinks> element is used to document personal or social relationships between individual participants, where this is felt to be of importance in the analysis. This may be done either as an informal prose description, or more formally using the special purpose <relation> element, as described below:
A relationship, as defined here, may be any kind of describable link between specified participants, for example a social relationship (such as employer/employee), a personal relationship (such as sibling, spouse, etc.) or something less precise such as ‘possessing shared knowledge’. A relationship may be mutual, in that all the participants engage in it on an equal footing (for example the ‘sibling’ relationship); or it may not be if participants are not identical with respect to their role in the relationship (for example, the ‘employer’ relationship). For non-mutual relationships, only two kinds of role are currently supported; they are named active and passive. These names are chosen to reflect the fact that non-mutual relations are directed, in the sense that they are most readily described by a transitive verb, or a verb phrase of the form ‘is X of’ or ‘is X to’. The subject of the verb is classed as active; the direct object of the verb, or the object of the concluding preposition, as passive. Thus parents are ‘active’ and children ‘passive’ in the relationship ‘parent’ (interpreted as ‘is parent of’); the employer is ‘active’, the employee ‘passive’, in the relationship ‘employs’. These relationships can be inverted: parents are ‘passive’ and children ‘active’ in the relationship ‘is child of’; similarly ‘works for’ inverts the active and passive roles of ‘employs’.
<particLinks> <relation desc="parent" active="p1 p2" passive="p3 p4" mutual="N"/> <relation desc="spouse" active="p1 p2" mutual="Y"/> <relation type="social" desc="employer" active="p1" passive="p3 p5 p6 p7" mutual="N"/> </particLinks>This example defines the following three relationships among participants P1 through P7:
<!-- 23.2.2: Participants description--> <!ELEMENT person %om.RO; (p+ | (%m.demographic;)* )> <!ATTLIST person %a.global; role CDATA #IMPLIED sex ( m | f | u ) #IMPLIED age CDATA #IMPLIED TEIform CDATA 'person' > <!ELEMENT personGrp %om.RO; (p+ | (%m.demographic;)* )> <!ATTLIST personGrp %a.global; role CDATA #IMPLIED sex ( m | f | u | x ) #IMPLIED age CDATA #IMPLIED size CDATA #IMPLIED TEIform CDATA 'personGrp' > <!ELEMENT birth %om.RR; %phrase.seq;> <!ATTLIST birth %a.global; date %ISO-date; #IMPLIED TEIform CDATA 'birth' > <!ELEMENT firstLang %om.RO; %phrase.seq;> <!ATTLIST firstLang %a.global; TEIform CDATA 'firstLang' > <!ELEMENT langKnown %om.RR; %phrase.seq;> <!ATTLIST langKnown %a.global; TEIform CDATA 'langKnown' > <!ELEMENT residence %om.RO; %phrase.seq;> <!ATTLIST residence %a.global; TEIform CDATA 'residence' > <!ELEMENT education %om.RO; %phrase.seq;> <!ATTLIST education %a.global; TEIform CDATA 'education' > <!ELEMENT affiliation %om.RR; %phrase.seq;> <!ATTLIST affiliation %a.global; TEIform CDATA 'affiliation' > <!ELEMENT occupation %om.RR; %phrase.seq;> <!ATTLIST occupation %a.global; scheme IDREF #IMPLIED code IDREF #IMPLIED TEIform CDATA 'occupation' > <!ELEMENT socecStatus %om.RO; %phrase.seq;> <!ATTLIST socecStatus %a.global; scheme IDREF #IMPLIED code IDREF #IMPLIED TEIform CDATA 'socecStatus' > <!ELEMENT particLinks %om.RO; (p+ | relation+) > <!ATTLIST particLinks %a.global; TEIform CDATA 'particLinks' > <!ELEMENT relation %om.RO; EMPTY> <!ATTLIST relation %a.global; type CDATA "personal" desc CDATA #IMPLIED active IDREFS #IMPLIED passive IDREFS #IMPLIED mutual (Y | N) "Y" TEIform CDATA 'relation' > <!-- end of 23.2.2-->
The <settingDesc> element is used to describe the setting or settings in which language interaction takes place. It may contain a prose description, analogous to a stage description at the start of a play, stating in broad terms the locale, or a more detailed description of a series of such settings. Individual settings may be associated with particular participants by means of the optional who attribute if, for example, participants are in different places. This attribute identifies one or more individual participants or participant groups, as discussed earlier in section 23.2.2 The Participants Description. If this attribute is not specified, the setting details provided are assumed to apply to all participants represented in the language interaction.165
<settingDesc> <p>The time is early spring, 1989. P1 and P2 are playing on the rug of a suburban home in Bedford. P3 is doing the washing up at the sink. P4 (a radio announcer) is in a broadcasting studio in London.</p> </settingDesc>The same information might be represented more formally in the following way:
<settingDesc> <setting who="p1 p2"> <name type="city">Bedford</name> <name type="region">UK: South East</name> <date value="1989">early spring, 1989</date> <locale>rug of a suburban home</locale> <activity>playing</activity> </setting> <setting who="p3"> <name type="city">Bedford</name> <name type="region">UK: South East</name> <date value="1989">early spring, 1989</date> <locale>at the sink</locale> <activity>washing-up</activity> </setting> <setting who="p4"> <name type="place">London, UK</name> <time>unknown</time> <locale>broadcasting studio</locale> <activity>radio performance</activity> </setting> </settingDesc>
For more detailed encoding of names of persons and places, the additional tag set described in chapter 20 Names and Dates may additionally be used; if used, however, these elements may appear only within a <p> element. The above examples assume that only the general purpose <name> element supplied in the core tag set is available. The elements discussed in this section have the following formal definitions:
<!-- 23.2.3: Setting description--> <!ELEMENT setting %om.RR; (p+ | (name | time | date | locale | activity)* )> <!ATTLIST setting %a.global; who IDREFS #IMPLIED TEIform CDATA 'setting' > <!ELEMENT locale %om.RO; %phrase.seq;> <!ATTLIST locale %a.global; TEIform CDATA 'locale' > <!ELEMENT activity %om.RO; %phrase.seq;> <!ATTLIST activity %a.global; TEIform CDATA 'activity' > <!-- end of 23.2.3-->
This section discusses the assocation of the contextual information held in the header with the individual elements making up a TEI text or corpus. Contextual information is held in elements of various kinds within the TEI header, as discussed elsewhere in this section and in chapter 5 The TEI Header. Here we consider what happens when different parts of a document need to be associated with different contextual information of the same type, for example when one part of a document uses a different encoding practice from another, or where one part relates to a different setting from another. In such situations, there will be more than one instance of a header element of the relevant type.
The TEI DTDs allow for the following possibilities:
A TEI conformant document may have more than one header only in the case of a TEI corpus, which must have a header in its own right, as well as the obligatory header for each text. Every element specified in a corpus-header is understood as if it appeared within every text header in the corpus. An element specified in a text header but not in the corpus header supplements the specification for that text alone. If any element is specified in both corpus and text headers, the corpus header element is over-ridden for that text alone.
The <titleStmt> for a corpus text is understood to be prefixed by the <titleStmt> given in the corpus header. All other optional elements of the <fileDesc> should be omitted from an individual corpus text header unless they differ from those specified in the corpus header. All other header elements behave identically, in the manner documented below. This facility makes it possible to state once for all in the corpus header each piece of contextual information which is common to the whole of the corpus, while still allowing for individual texts to vary from this common denominator.
For example, the following schematic shows the structure of a corpus comprising three texts, the first and last of which share the same encoding declaration. The second one has its own encoding declaration
<teiCorpus.2> <teiHeader> <!-- contains declarations common to the whole corpus --> <fileDesc> <!-- ... --> </fileDesc> <encodingDesc> <!-- for example, this encodingDesc is common to whole corpus. --> <!-- ... --> </encodingDesc> <revisionDesc> <!-- ... --> </revisionDesc> </teiHeader> <TEI.2> <teiHeader> <fileDesc> <!-- details peculiar to this text --> </fileDesc> </teiHeader> <text> <!-- ... --> </text> </TEI.2> <TEI.2> <teiHeader> <fileDesc> <!-- details peculiar to this text --> </fileDesc> <encodingDesc> <!-- encoding description peculiar to this text --> </encodingDesc> </teiHeader> <text> <!-- ... --> </text> </TEI.2> <TEI.2> <teiHeader> <fileDesc> <!-- details peculiar to this text --> ... </fileDesc> </teiHeader> <text> <!-- ... --> </text> </TEI.2> </teiCorpus.2>
Certain of the elements which can appear within a TEI Header are known as declarable elements. These elements have in common the fact that they may be linked explicitly with a particular part of a text or corpus by means of a decls attribute. This linkage is used to over-ride the default association between declarations in the header and a corpus or corpus text. The only header elements which may be associated in this way are those which would not otherwise be meaningfully repeatable. An alphabetically ordered list of declarable elements follows:
In the following example, an editorial declaration contains two possible <correction> policies, one identified as C1 and the other as C2. Since there are two, one of them (in this case C1) must be specified as the default:
<editorialDecl> <correction id="c1" default="YES"> <p> ... </p> </correction> <correction id="c2"> <p> ... </p> </correction> <normalization id="n1"> <p> ... </p> <p> ... </p> </normalization> </editorialDecl>For texts associated with the header in which this declaration appears correction method C1 will be assumed, unless they explicitly state otherwise. Here is the structure for a text which does state otherwise:
<text> <body> <!-- ... --> <div1 n='d1'> <!-- ... --> </div1> <div1 n='d2' decls='C2'> <!-- ... --> </div1> <div1 n='d3'> <!-- ... --> </div1> <!-- ... --> </body> </text>In this case, the contents of the divisions D1 and D3 will both use correction policy C1, and those of division D2 will use correction policy C2.
The decls attribute is defined for any element which is a member of the class declaring. This includes the major structural elements <text>, <group>, and <div>, as well as smaller structural units, down to the level of paragraphs in prose, individual utterances in spoken texts, and entries in dictionaries. However, TEI recommended practice is to limit the number of multiple declarable elements used by a document as far as possible, for simplicity and ease of processing.
The identifier or identifiers specified by the decls attribute are subject to two further restrictions:
<encodingDesc> <!-- ... --> <editorialDecl id='ED1' default='YES'> <correction id='C1A' default='YES'> <p> ... </p></correction> <correction id='C1B'> <p> ... </p></correction> <normalization id="N1"> <p> ... </p> <p> ... </p> </normalization> <p> ... </p> <p> ... </p> </editorialDecl> <editorialDecl id='ED2'> <correction id='C2A' default='YES'> <p> ... </p></correction> <correction id='C2B'> <p> ... </p></correction> <normalization id='N2A'> <p> ... </p></normalization> <normalization id='N2B' default='YES'><p> ... </p></normalization> <p> ... </p> </editorialDecl> <!-- ... --> </encodingDesc>
This encoding description now has two editorial declarations, identified as ED1 (the default) and ED2. For texts not specifying otherwise, ED1 will apply. If ED1 applies, correction method C1a and normalization method N1 apply, since these are the specified defaults within ED1. In the same way, for a text specifying decls as ‘ED2’, correction C2a, and normalization N2b will apply.
A finer grained approach is also possible. A text might specify <text decls='C2b N2a'>, to `mix and match' declarations as required. A tag such as <text decls='ED1 ED2'> would (obviously) be illegal, since it includes two elements of the same type; a tag such as <text decls='ED2 C1a'> is also illegal, since in this context ‘ED2’ is synonymous with the defaults for that editorial declaration, namely ‘ C2a N2b’, resulting in a list that identifies two correction elements (C1a and C2a).
The rules determing which of the declarable elements are applicable at any point may be summarized as follows:
Language corpora often include analytic encodings or annotations, designed to support a variety of different views of language. The present Guidelines do not advocate any particular approach to linguistic annotation (or `tagging'); instead a number of general analytic facilities are provided which support the representation of most forms of annotation in a standard and self-documenting manner. Analytic annotation is of importance in many fields, not only in corpus linguistics, and is therefore discussed in general terms elsewhere in the Guidelines.166 The present section presents informally some particular applications of these general mechanisms to the specific practice of corpus linguistics.
By linguistic annotation we mean here any annotation determined by an analysis of linguistic features of the text, excluding as borderline cases both the formal structural properties of the text (e.g. its division into chapters or paragraphs) and descriptive information about its context (the circumstances of its production, its genre or medium). The structural properties of any TEI-conformant text should be represented using the structural elements discussed elsewhere in this chapter and in chapters 6 Elements Available in All TEI Documents, 7 Default Text Structure, and the various chapters of Part III (on base tag sets). The contextual properties of a TEI text are fully documented in the TEI Header, which is discussed in chapter 5 The TEI Header, and in section 23.2 Contextual Information of the present chapter.
Other forms of linguistic annotation may be applied at a number of levels in a text. A code (such as a word-class or part-of-speech code) may be associated with each word or token, or with groups of such tokens, which may be continuous, discontinuous or nested. A code may also be associated with relationships (such as cohesion) perceived as existing between distinct parts of a text. The codes themselves may stand for discrete non-decomposable categories, or they may represent highly articulated bundles of textual features. Their function may be to place the annotated part of the text somewhere within a narrowly linguistic or discoursal domain of analysis, or within a more general semantic field, or any combination drawn from these and other domains.
The manner by which such annotations are generated and attached to the text may be entirely automatic, entirely manual or a mixture. The ease and accuracy with which analysis may be automated may vary with the level at which the annotation is attached. The method employed should be documented in the <interpretation> element within the encoding description of the TEI Header, as described in section 5.3.3 The Editorial Practices Declaration. Where different parts of a corpus have used different annotation methods, the decls attribute may be used to indicate the fact, as further discussed in section 23.3 Associating Contextual Information with a Text.
An extended example of one form of linguistic analysis commonly practised in corpus linguistics is given in section 15.4 Linguistic Annotation.
These Guidelines include proposals for the identification and encoding of a far greater variety of textual features and characteristics than is likely to be either feasible or desirable in any one language corpus, however large and ambitious. The reasoning behind this catholic approach is further discussed in chapter 1 About These Guidelines. For most large scale corpus projects, it will therefore be necessary to determine a subset of TEI recommended elements appropriate to the anticipated needs of the project. Mechanisms for tailoring the TEI dtd to implement such a subset are described in chapter 3 Structure of the TEI Document Type Definition and chapter 29 Modifying and Customizing the TEI DTD; they include the ability to exclude selected element types, add new element types, and change the names of existing elements. A discussion of the implications of such changes for TEI conformance is provided in chapter 28 Conformance.
Because of the high cost of identifying and encoding many textual features, and the difficulty in ensuring consistent practice across very large corpora, encoders may find it convenient to divide the set of elements to be encoded into the following three categories: