en:cnk:lemtag_mluv - Příručka ČNK

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====== Lemmatization and tagging in spoken corpora ======

Lemmatizing and tagging a transcription of spoken language is much more demanding than for written language. There is a larger amount of unknown forms (reduced pronunciation, dialectal forms, neologisms), which can be homonymous with forms contained in the morphological dictionary for written language (e.g. //pudu// as recorded pronunciation of the verbal form //půjdu// is homonymous with the dative and locative forms of the noun //pud// and with the recorded shortened pronunciation of the plural genitive of the noun //půda//). The distinct structure of informal dialogue, which is characterized by the quantity of unfinished, interrupted and modified utterances, repeated words, filler sounds, references to the extralinguistic context etc., makes the identification of morphological categories difficult even for linguists. 
With regard to the size of the corpus, lemmatization, in particular, is indispensable, without which it would be virtually impossible to find all forms of a given lemma (for example reduced and dialectal forms). Due to the mode of transcription (namely the use of pause punctuation in the place of syntactic punctuation), tools and procedures commonly used for written language cannot be used. 

The following method for lemmatization and morphological tagging has been used for the [[en:cnk:oral|ORAL]], [[en:cnk:ortofon|ORTOFON]] and [[en:cnk:dialekt|DIALEKT]] corpora. Its primary contribution lies in the lemmatization and tagging of word classes. However, it is recommended to carefully double check this when searching, especially in the case of morphological categories.

The lemmatization and tagging method used, although laborious, is only the first attempt to facilitate working with the extensive data of the ORAL, ORTOFON and DIALEKT corpora, and as such contains errors and inaccuracies, which in turn lead to more general questions regarding the notion of tagging spoken corpora. It is hoped that these will be solved in the upcoming versions by the creation of a new tagging scheme (NovaMorf) and tools for its implementation. Despite these shortcomings, this corpus provides vastly improved conditions for working with spoken data in comparison to previous corpora.

**Concept of lemma**

The concept of lemma is broader than in written language. The main priority is to be able to find all forms of a given words, which can be recorded with reduced pronunciation, but also dialectal forms, which could have a separate lemma (e.g. //týden – tejden – tédeň – tydeň//). Large-scale variation is typical namely for demonstrative pronouns e.g. lemma **tenhleten** contains 105 word forms (e.g. nom. sg. neut. can be written in the following ten ways: //tohleto, todnecto, todleto, todlecto, todlencto, tohlencto, tohlento, toleto, tohlensto, todlensto//).

**Tagging method**

[[en:seznamy:tagy#pozice_1_-_slovni_druh|The morphological tagging system]] is the same as for written corpora, however, some tags for associated categories are retained (e.g. X for any gender, Y for masculine animate or inanimate etc.) just as they are contained in the morphological dictionary MorfFlex CZ (Hajič–Hlaváčová, 2013). This dictionary was manually and semiautomatically supplemented by frequently unrecognised forms (e.g. dialectal suffixes, forms with varying quantity, prothetic v). The stochastic tagging system MorphoDiTa (Straka a kol., 2014) was used for the tagging itself.

===== Modifications to the morphological dictionary =====

The original morphological dictionary MorfFlex CZ (Hajič–Hlaváčová, 2013) was manually and semiautomatically supplemented, edited, and selected interpretations of grammatical categories were omitted with regard to the target register (e.g. the form //bej// in spoken data represents only a reduced variant of the verb //být//, and not a noun). Unrecognised forms were added from a frequency of 5 occurrences or higher. 
Examples of some modifications:

**Semiautomatic additions**:
  * **dialectal suffixes** such as the acc. sg. fem. ending with -u (//nedělu, chvilu//), verbal forms of the past active participle (//dělale, chodile//)
  * variants differing in **vowel quantity** (//myslim, vim, makem, polivka//), **palatalization** (//tydeň//), **the presence of a prothetic v-** (//vokýnko, vobrazovka//)
  * "mapping" unknown forms to familiar forms (with all of their morphological interpretations)

**Manual additions**:
  * assigning and merging **výslovnostních variant** (např. //třeba, čovek, depák; dokavád, dovaď, dovad//) pod jedno lemma 
  * přiřazení **nářečních podob** (//dňama, Davidoj, ňou//) ke spisovnému lemmatu


**Odstranění některých interpretací**:
  * odstranění interpretace výrazu jako adverbium: //prostě//
  * odstranění interpretace výrazu jako imperativ: //viď//
  * odstranění interpretace výrazu jako vokativ: //pote// (redukovaná výslovnost //pojďte//)

**Doplnění některých interpretací**
  * přidání kategorie částice: //jen// (původně pouze adverbium)
  * změna interpretace: //puč// neoznačujeme jako substantivum, jedná se o redukovanou výslovnost imperativu slovesa //půjčit// 
===== Podoba lemmatu =====

  * většina slov má lemma v podobě **spisovného lemmatu**, tedy stejnou jako v psaném jazyce, a to i v případech, kdy regionální podoba frekvenčně převažuje (např. pod lemma **//týden//** spadají všechny tvary regionálních variant //tejden, tyden, tydeň, tédeň//)
  * slova s** dvojí spisovnou podobou** mají vícenásobné lemma (//polívka/polévka//)
  * slova, u nichž **nelze jednoznačně přiřadit jednotlivé tvary**, mají také vícenásobné lemma (//myslet/myslit, muset/musit//)
  * **zkratky** mají vícenásobné lemma: //SMS/esemeska, endéer/NDR// 

Vícenásobné lemma funguje jako multihodnota, to znamená, že při zadání jedné z možností vždy dostaneme všechny tvary přiřazené k vícenásobnému lemmatu.


===== Tag forms=====

The form of the tags corresponds to that of the [[en:seznamy:tagy#pozice_1_-_slovni_druh|morphological tags]] used in the [[en:cnk:syn|SYN]] series written corpora before the simplification of the tagging system and does not include aspect in the 16th position.
Apart from these tags, the first position for the word class and the POS attribute can have the following values:

  * **F** for unfinished words (e.g. //nepoda*//)
  * **H** for non-verbal sounds (hesitations, marked @, responsive //hmm, emm//)
  * **M** for comments (always in round brackets)

===== Acknowledgements =====
We would like to thank doc. Klára Osolsobě and Mgr. Dana Hlaváčková, Ph.D. for providing valuable consultations. 

===== Sources =====

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Kopřivová, M. - Lukeš, D. - Komrsková, Z. - Poukarová, P.: Korpus ORAL: sestavení, lemmatizace a morfologické značkování. In //Korpus - Gramatika - Axiologie// 2017 (in print).

Lukeš. D. - Klimešová, P. - Komrsková, Z. - Kopřivová, M. (2015): Experimental Tagging of the ORAL Series Corpora: Insights on Using a Stochastic Tagger. In: TSD 2015, Ed. P. Král a V. Matoušek. Springer International Publishing, 342-350.
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===== Related links =====

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[[en:cnk:oral|ORAL]] • [[en:cnk:ortofon|ORTOFON]] • [[en:cnk:dialekt|Dialekt]] • [[en:pojmy:mluveny|Spoken language corpus]] • [[en:pojmy:atributy_strukturni#strukturni_atributy_korpusu_rady_oral|Structure of the ORAL corpora]] • [[en:kurz:hledani_v_mluvenych_korpusech|Searching in spoken corpora]] • [[en:kurz:hledani_ORTOFON|Searching in the ORTOFON corpus]] • [[en:cnk:dialekt:prace|Searching in the DIALEKT corpus]]
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Trace: • filtr • korpusy • syn2013pub • olgarichterova • verze5 • pmk • tokenizace • kwords • online • uvod
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