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Universal Dependencies

<span property="owl:versionInfo"> These pages draw from Section 2 of *[Stanford typed dependencies manual](http://nlp.stanford.edu/software/dependencies_manual.pdf)* (de Marneffe and Manning 2008), but have been updated for UD.
</span> </span>

English grammatical relations en

Note: nmod, neg and punct appear in two places.

Core dependents of clausal predicates
Nominal dep Predicate dep
nsubj csubj
nsubjpass csubjpass
dobj ccomp xcomp
iobj
Non-core dependents of clausal predicates
Nominal dep Predicate dep Modifier word
  advcl advmod
nmod   neg
nmod:npmod
nmod:tmod
nmod:poss
Special clausal dependents
Nominal dep Auxiliary Other
vocative aux mark
discourse auxpass punct
expl cop
Noun dependents
Nominal dep Predicate dep Modifier word
nummod acl amod
  acl:relcl
appos   det
    det:predet
nmod   neg
Compounding and unanalyzed
compound mwe goeswith
compound:prt
name foreign
Coordination
conj cc punct
  cc:preconj
Case-marking, prepositions, possessive
case
Loose joining relations
list parataxis remnant
dislocated reparandum
Other
Sentence head Unspecified dependency
root dep

acl:
clausal modifier of noun

acl is used for finite and non-finite clauses that modify a noun. Note that in English relative clauses get assigned a specific relation acl:relcl, a subtype of acl.

Non-relative clause finite clausal complements for nouns are limited to complement clauses with a subset of nouns like fact or report. We analyze them as acl (parallel to the analysis of this class as “content clauses” in Huddleston and Pullum 2002). Such clausal complements are usually finite (though there are occasional remnant English subjunctives).

edit acl

acl:relcl:
relative clause modifier

A relative clause modifier of an noun is a relative clause modifying the noun. The relation points from the noun that is modified to the head of the relative clause. Relative clauses are finite.

edit acl:relcl

advcl:
adverbial clause modifier

An adverbial clause modifier is a clause which modifies a verb or other predicate (adjective, etc.), as a modifier not as a core complement. This includes things such as a temporal clause, consequence, conditional clause, purpose clause, etc. The dependent must be clausal (or else it is an advmod) and the dependent is the main predicate of the clause.

edit advcl

advmod:
adverbial modifier

An adverbial modifier of a word is a (non-clausal) adverb or adverbial phrase (ADVP) that serves to modify the meaning of the word.

edit advmod

case:
case marking

The case relation is used for any preposition in English. Prepositions are treated as dependents of the noun they attach to or introduce in an “extended nominal projection”. Thus, contrary to SD, UD abandons treating a preposition as a mediator between a modified word and its object. The case relation aims at providing a uniform analysis of prepositions and case in morphologically rich languages. In English, subordinating conjunctions introducing clauses are often in the form of prepositions. However, they are given a different dependency: The relation mark is used for markers in an “extended clausal projection”.

The case relation is also used for the possessive clitic ‘s in English, which we separate from what it modifies, because it acts as a phrasal clitic, as shown in the last example.

edit case

compound:
compound

compound is used for:

  • noun compounds. (These should show the correct modification structure of noun compounds, and do - or should - in the English UD treebank. Note, however, that the current automatic Stanford UD converter still makes all nouns modify the rightmost noun of the noun phrase when run on corpora like the 1999 Penn Treebank 3 which do not show noun compound structure - there is no intelligent noun compound analysis. The correct results are achieved when run on corpora like OntoNotes which do represent the branching structure of noun phrases.)

This includes proper names that use regular syntactic relations—contrast with name:

  • numbers
  • adjectival compounds
  • imitative reduplication
  • idiomatic phrasal verbs are analyzed as a language-specific subrelation of compound
edit compound

compound:prt:
phrasal verb particle

The phrasal verb particle relation identifies an idiomatic phrasal verb, and holds between the verb and its particle (tagged as ADP). It is a subtype of the compound relation.

This relation excludes literal/directional uses of prepositions/particles, such as up, down, in, out, etc. These would typically become an ADV with the relation advmod:

edit compound:prt

cop:
copula

A copula is the relation between the complement of a copular verb and the copular verb. Copular heads are avoided when possible.

Prepositional phrases are annotated similarly, the only difference being that the nominal predicate has an additional case marker.

When an adjective or adverb is being predicated of a nominal phrase, the adjective/adverb is the root, the nominal phrase is the nsubj, and the copula is the cop.

Prepositions may also project a cop dependent.

In predicative wh-constructions, the fronted wh-word is the head, and the copula is another cop.

However, whenever the copula has a clausal argument/adjunct, the copula becomes the root, so the cop relation is not used.

Predicative “be” is the only verb recognized as a copula; other copula-like verbs,such as “become”, “get”, and “seem”, are treated as regular raising verbs, and thus take xcomp arguments. Non-predicative uses of “be”–e.g., “be” when used in periphrastic verbal constructions, presentationals, or existentials–is annotated as an aux instead. of a cop.

edit cop

list:
list

The list relation is used for chains of comparable items. Web text often contains passages which are meant to be interpreted as lists but are parsed as single sentences. Email signatures in particular contain these structures, in the form of contact information: the different contact information items are labeled as list; the key-value pair relations are labeled as appos.

In lists with more than two items, all items of the list shoud modify the first one.

In an itemized or numbered list, we have been taking the item marker as a dependent of the head of the contentful list item. This appears to be better than the alternative.

edit list

mark:
marker

A marker is the word introducing a clause subordinate to another clause. For a complement clause, this will typically be that or whether. For an adverbial clause, the marker is typically a preposition like before or a subordinating conjunction fulfilling a similar role like while or although. The mark is a dependent of the subordinate clause head.

The infinitive marker to is analyzed as a mark.

When a a noun or a verb takes a prepositionally marked non-core argument (modifier) and that modifier is a clause, then we also label that prepositon as mark (as it would not seem reasonable to call it case when it is marking a clause). The result will commonly be a doubly marked clause.

edit mark

mwe:
multi-word expression

The multi-word expression (modifier) relation is used for certain fixed grammaticized expressions with function words that behave like a single function word. Multiword expressions are annotated in a flat, head-initial structure, in which all words in the expression modify the first one using the mwe label.

At present, this relation is used inside the following expressions:

as well

as well as

such as

due to (and other forms, such as d t and d/t)

because of (and other forms, such as b c of and b/c of)

instead of

in case

in case of

of course

so that

more than (when used synonymously with “over” in a quantity)

less than (when used synonymously with “under” in a quantity)

up to (when used in quantities)

according to

in order

rather than

at least (when not used for quantities)

as if

prior to

as to

kind of

whether or not

not to mention

as opposed to

let alone

so as to

in between

all but

that is

how come

had better (and ‘d better)

Not mwes

The following are not annotated as mwes, but are instead labeled according to their apparent internal structure.

out of, off of (All double prepositions denoting spatial relations are annotated with two cases on the nominal)

by far

what about

at all

at most, at least (when used for quantities. To determine whether at least should be an mwe or not in borderline cases, substitute it with at most; if the sentence remains grammatical, it should receive its surface analysis)

at best, at worst

what if

so long

edit mwe

name:
name

name is one of the three relations for compounding in UD (together with compound and mwe). It is used for proper nouns constituted of multiple nominal elements. For example, name would be used between the words of Hillary Rodham Clinton, New York, or Carl XVI Gustaf but not to replace the usual relations in a phrasal or clausal name like The king of Sweden or the novels The Lord of the Rings and Captured By Aliens. Words joined by name should all be part of a minimal noun phrase; otherwise regular syntactic relations should be used. This is basically similar to the treatment of noun compounds with compound, except that in many cases parts of the name may be another nominal element such as an adjective (United Airlines).

In general, names are annotated in a flat, head-initial structure, in which all words in the name modify the first one using the name label.

For organization names with clear syntactic modification structure, the dependencies should reflect the syntactic modification structure using regular syntactic relation, as in:.

In addition, regular syntactic relations are used: (i) for a modifying English determiner or (ii) to connect together the words of a description or name which involve English embedded prepositional phrases, sentences, etc.

If a name contains a function word in another language than English, we also use the name relation.

edit name

nmod:
nominal modifier

The nmod relation is used for nominal modifiers of nouns or clausal predicates. nmod is a noun functioning as a non-core (oblique) argument or adjunct. In English, nmod is used

  • for prepositional complements (including datives and partitives):

The nmod relation holds between the noun/predicate modified by the prepositional complement and the noun introduced by the preposition.

  • for ‘s genitives:

Nominal modifiers not marked by a preposition or ‘s genitive are tagged nmod:npmod, a subtype of nmod. Temporal nominal modifiers are also marked with a separate relation nmod:tmod. See the definitions of these relations.

edit nmod

nmod:npmod:
noun phrase as adverbial modifier

This relation is a subtype of the nmod relation, which captures the following cases where something syntactically a noun phrase is used as an adverbial modifier in a sentence:

(i) a measure phrase, which is the relation between the head of an adjectival/adverbial or prepositional phrase and the head of a measure phrase modifying it:

(ii) noun phrases giving an extent to a verb, which are not objects:

(iii) financial constructions involving an adverbial, notably the following construction $5 a share, where the second nominal means “per share”:

(iv) floating reflexives

and (v) certain other absolutive nominal constructions.

A temporal modifier nmod:tmod is a subclass of npmod which is distinguished as a separate relation.

edit nmod:npmod

nmod:tmod:
temporal modifier

A temporal modifier is a subtype of the nmod relation: if the modifier is specifying a time, it is labeled as tmod.

edit nmod:tmod

nsubj:
nominal subject

A nominal subject (nsubj) is a nominal which is the syntactic subject and the proto-agent of a clause. That is, it is in the position that passes typical grammatical test for subjecthood, and this argument is the more agentive, the do-er, or the proto-agent of the clause. (See csubj for when the subject is clausal. See nsubjpass and csubjpass for when the subject is not the proto-agent argument due to valence changing operations.) This nominal may be headed by a noun, or it may be a pronoun or relative pronoun, or in ellipsis contexts, other things such as an adjective.

The nsubj role is only applied to semantic arguments of a predicate. When there is an empty argument in a grammatical subject position (sometimes called a pleonastic or expletive), it is labeled as expl. If there is then a displaced subject in the clause, as in the English existential there construction, it will be labeled as nsubj. The governor of the nsubj relation might not always be a verb: when the verb is a copular verb, the root of the clause is the complement of the copular verb, which can be an adjective or noun, including a noun marked by a preposition, as in the examples below.

In English, the nsubj normally precedes the predicate that it depends on, but this need not be the case, both for the displaced subjects of expletive constructions and in other cases of stylistic inversion, such as the example headed by the predicate come below.

edit nsubj

parataxis:
parataxis

The parataxis relation (from Greek for “place side by side”) is a relation between the main verb of a clause and other sentential elements, such as a sentential parenthetical, a clause after a “:” or a “;”, or two sentences placed side by side without any explicit coordination or subordination.

When multiple parataxes are present in a single sentence, they get a flat structure, not a hierarchical one, even if they form a temporal sequence.

All else being equal, the leftmost phrase should be the head, but in rare situations the parataxis can go ``backwards’’:

See also: language-general documentation of parataxis

edit parataxis

remnant:
remnant in ellipsis

The remnant relation is used to provide a satisfactory treatment of ellipsis (in the case of gapping and stripping, where a predicational or verbal head gets elided) without having to postulate empty nodes in the basic representation. This is something that was lacking in earlier versions of SD and provides a basis for being able to reconstruct dependencies in the enhanced representation of SD.

USD adopts an analysis that notes that in ellipsis a remnant corresponds to a correlate in a preceding clause. The remnant relation connects each remnant to its correlate in the basic dependency representation. This is then a sufficient representation to reconstruct the predicate-argument structure in the enhanced representation.

Even in the more complex example below, the remnant relations enable us to correctly retrieve the subjects and objects in the clauses with an elided verb.

Note in particular that (unlike for conj), remnant uses a chaining analysis where each subsequent remnant depends on the immediately preceding remnant/correlate. The reason for this is that otherwise in a sentence with 2 or more chained ellipses the dependency structure would no longer track which remnants go together. It would become impossible to determine whether Mary won silver and Sandy gold, or Mary won gold and Sandy silver.

Instances of stripping typically occur when there is only one argument in the second clause, but with an accompanying adverbial modifier such as not or only. We model these sentences with the remnant relation as well.

Sometimes in these constructions adverbials will be “sprouted”, and have no correlate in the precedeing clause. In such a situation, the adverbial should attach to one of the remnants; in principle it shouldn’t matter which remnant it attaches to, since all remnants at a particular depth of embedding point back to the same semantic event (which the adverbial is a part of). However, to enforce a regular system, the adverbial should depend on the nearest leftmost dependent.

The remnant relation is used when no predicational material is present. In contrast, in right-node-raising (RNR) and VP-ellipsis constructions in which some kind of predicational or verbal material is still present, the remnant relation is not used. In RNR, the verbs are coordinated and the object is a dobj of the first verb:

In VP-ellipsis, we keep the auxiliary as the head, as shown below:

edit remnant

xcomp:
open clausal complement

An open clausal complement (xcomp) of a verb or an adjective is a predicative or clausal complement without its own subject. The reference of the subject is necessarily determined by an argument external to the xcomp (normally by the object of the next higher clause, if there is one, or else by the subject of the next higher clause. These complements are always non-finite, and they are complements (arguments of the higher verb or adjective) rather than adjuncts/modifiers, such as a purpose clause. The name xcomp is borrowed from Lexical-Functional Grammar.

edit xcomp
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