UD for Russian 
Tokenization and Word Segmentation
- In general, words are delimited by whitespace characters.
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According to typographical rules, many punctuation marks and special symbols ($, %) are attached to a neighboring word. We tokenize them as separate tokens (words) in most cases. Description of exceptions follows:
- conventional multi-character punctuation marks: – , … , ?! and emojis and smileys: :) , ^_^;
- abbreviations such as т.д. “etc.” (two tokens instead of four). If the period overlaps with the end of sentence period then it is written only once as a separate token (denoting end-of-sentence);
- hyphenated compounds such as премьер-министр “prime minister” (one token instead of three) (if the first part of the compound is not inflected);
- prepositions such as из-за “because of” (one token instead of two);
- alphanumeric compounds with hyphen such as 5-летняя девочка “5-years-old girl” (two tokens instead of four);
- numerical expressions including decimal numbers, such as 245000, 3,14, are treated as single tokens;
- time expressions such as 20:55 are treated as a single token;
- dates such as 20.04.2012 are treated as a single token;
- email addresses, URLs, and tweet-style names are treated as a single token: {no@mail.ru}, {https://github.com}, {@anna_li};
- discoursive particles such as -то and -с are tokenised as separate tokens, e.g. Вася-то is tokenized as 3 tokens. Exceptions: indefinite pronouns and adverbs, see below.
- Pronouns and adverbs
- Indefinite pronouns and adverbs like кто-нибудь, кто-либо, кто-то, кое-кто “someone, somebody”, etc. are treated as a single token;
- In prepositional phrases, the pronouns with кое- are treated as separate tokens: e.g. кое к кому “to someone” is tokenized as 3 tokens;
- Negative pronouns, adverbs and adverbial predicatives are treated as a single token, e.g. никто “no one”, никакой “no, neither”, нигде “nowhere”, негде “there is no place”. However, in prepositional phrases, negative pronouns and predicatives are splitted into 3 tokens: e.g. ни к кому “to no one”, не от кого “from no one”.
- Verb forms, analytical grammatical forms, negation
- reflexive verbs are treated as a single token (orthographic rule): моется “wash oneself”;
- не and ни used as negation markers are tokenized according to the orthographic rules: e.g. не реагируя “not reacting”, ни в какую “in no way”, but непоправимый “irrecoverable”, назавершенный “unfinished”;
- пол- and полу- “half” are treated as single tokens: поллитра “half a liter”, пол-яблока “half an apple”.
Russian UD treebanks do not contain multiword tokens.
Morphology
Tags
All corpora use the full range of UPOS tags. The XPOS column uses a version of the Penn Treebank tagset in GSD and Taiga treebanks, see https://github.com/olesar/ruUD/blob/master/conversion/RussianUD_XPOSlist.md.
Features
Morphological features are included in all corpora. In GSD and Taiga, they are tagged manually, in Syntagrus, they are converted from the features manually tagged in the source treebank. In PUD, they are added automatically and then manually checked.
The following feature subtypes are used in Russian:
- Variant distinguishes short and long forms of adjectives.
The following universal features are not used in Russian: Clusivity, Definite, Evident, NounClass, Polite.
Syntax
Core Arguments, Oblique Arguments and Adjuncts
- Nominal subject (nsubj) is prototypically a noun phrase in the nominative case, without a preposition.
- If the noun phrase is quantified, it may be in the genitive, which is required by the quantifier. If this is the case, then the quantifier is attached using a special relation, either nummod or nummod:gov.
- In distributive constructions, the nominal subject is used in the dative case, to which the preposition po is attached.
- Under negation, the noun phrase is used in the genitive case.
- Clausal subjects (csubj) are typically infinitival verbs or the heads of subordinate clauses. This is mostly the case of predicative constructions or nominative copular constructions.
- Note that verbal nouns as subjects are labeled
nsubj.
- Note that verbal nouns as subjects are labeled
- In passive clauses, the subject is labelled with nsubj:pass or csubj:pass. Auxiliary verbs in periphrastic passive are labelled aux:pass.
- If a semantic agent is present, it has the form of the instrumental case, and its relation is labelled obl:agent.
- Nominal direct objects are labeled obj. They usually occur in the accusative case (but not all bare accusative nominals are objects), but in some cases, instrumental and genitive nominals can be direct objects as well.
- All other required dependents of verbs in the dative and instrumental cases are indirect objects (iobj).
- Required clausal dependents of verbs are marked as ccomp, unless they are subjects (csubj).
- Open (“controlled”) clausal dependents are labeled xcomp; they are mostly infinitival complements of verbs such as начать “begin”.
- Instrumental/nominative nominal dependents of verbs such as быть “be”, стать “become”, работать “work (as)”, считать “consider (as)” are also labeled xcomp.
- Prepositional phrases are labeled obl. These include:
- core arguments of verbs, adjectives and other predicates;
- adjuncts (or, following the Russian grammar, adverbial modifiers realized as prepositional noun phrases).
- Temporal and other circumstantial modifiers as well as benefactives realized as bare noun phrases: подумал минуту “he thought for a minute”, сварила ему обед “she cooked him a lunch” are also labeled obl.
- In comparative constructions, the genitive noun phrase that refers to the standard of comparison is labeled obl.
- The vocative relation is used to attach a participant addressed in the dialogue.
Copula Clauses
- The copula verb быть “be” is used in equational, attributional, locative, and benefactive nonverbal clauses.
Purely existential clauses use быть as well but it is treated as the head of the clause and tagged VERB.
In possessive clauses, быть is treated differently in different treebanks.
Note that the copula verb is rarely used in the present tense in Russian.
Expletives
- The particle это “this” used in equational clauses with meaningful subject is labeled expl: Государство - это я “The state is Me.” Pleonastic это in clauses with overt nominative subject is also labeled expl: Это Лена пришла “This (is) Lena came.”
- If there is no other subject, это “this” is treated as a subject and tagged PRON: Это Лена “This (is) Lena”, Это еще к чему? “What purpose is it for?”
Adjectival Clauses
- Relational clauses are labeled acl:relcl.
- Participle phrases are labeled acl.
- Participles that do not have dependents are labeled amod.
- Floating quantifiers сам “oneself”, один “alone”, весь “all”, оба “both” are labeled acl.
- Secondary non-core arguments in depictive constructions are labeled acl: Он пришел домой усталый “He came home tired.”
Nominal phrases
- The following relations are used to attach elements to the head of the nominal phrase:
Function words
- The following relations are used to attach the function words:
Other relations
- root for the root of the sentence
- orphan for orphan relations in ellipsis
- list for chains of items in the list
- fixed for tokens in the multiword expression
- flat for other flat relations
- goeswith for elements written separately in not well edited texts
- dep for unspecified dependency
Relations Overview
- The following relation subtypes are used in Russian:
- nsubj:pass for nominal subjects of passive verbs
- csubj:pass for clausal subjects of passive verbs
- aux:pass for passive auxiliaries
- obl:agent for agents of passive verbs
- acl:relcl for the traditional class of relative clauses
- nummod:gov for cardinal numbers that are attached as children of the counted noun but govern its case
- nummod:entity numeric modifier governed by a noun
- flat:foreign for non-first words in quoted foreign phrases
- flat:name for non-first words in multiword proper names
- clf is not used in Russian.
Treebanks
There are four Russian UD treebanks: