Universal Stanford Dependencies: A cross-linguistic typology
Marie-Catherine de Marneffe◦ , Timothy Dozat? , Natalia Silveira? ,Katri Haverinen• , Filip Ginter• , Joakim Nivre/ , Christopher D. Manning?
◦?

Linguistics Department, The Ohio State University
Linguistics and  Computer Science Departments, Stanford University•
Department of Information Technology, University of Turku/
Department of Linguistics and Philology, Uppsala University
Abstract

Revisiting the now de facto standard Stanford dependency representation, we propose an improved taxonomy to capture grammatical
relations across languages, including morphologically rich ones. We suggest a two-layered taxonomy: a set of broadly attested
universal grammatical relations, to which language-specific relations can be added. We emphasize the lexicalist stance of the Stanford
Dependencies, which leads to a particular, partially new treatment of compounding, prepositions, and morphology. We show how
existing dependency schemes for several languages map onto the universal taxonomy proposed here and close with consideration ofpractical implications of dependency representation choices for NLP applications, in particular parsing.
Keywords: dependency grammar, Stanford Dependencies, grammatical taxonomy

1.

Introduction

The Stanford Dependencies (SD) representation (deMarneffe et al., 2006) was originally developed as a practical representation of English syntax, aimed at natural language understanding (NLU) applications. However, it was
deeply rooted in grammatical relation-based syntactic traditions, which have long emphasized cross-linguistic description. Faithfulness to these origins was attenuated bydesiderata from our NLU applications and the desire for a
simple, uniform representation, which was easily intelligible by non-experts (de Marneffe and Manning, 2008). Nevertheless, it is reasonable to suppose that these additional
goals do not detract from cross-linguistic applicability.
In this paper, we attempt a (post-hoc) reconstruction of
the underlying typology of the Stanford Dependencies representation. This not only gives insights into how the approach might be applied to other languages, but also gives
an opportunity to reconsider some of the decisions made in
the original scheme, aiming to propose an improved taxonomy, even for English. We suggest a taxonomy which has
at its core a set of very broadly attested grammatical relations, supplemented as needed by subtypes for languageparticular relations, which capture phenomena important tothe syntax of individual languages or language families.
We attempt to make the basic core more applicable, bothcross-linguistically and across genres, and more faithful tothe design principles in de Marneffe & Manning (2008).
We consider how to treat grammatical relations in morphologically rich languages, including achieving an appropriate parallelism between expressing grammatical relations
by prepositions versus morphology. We show how existing
dependency schemes for other languages which draw from
Stanford Dependencies (Chang et al., 2009; Bosco et al.,2013; Haverinen et al., 2013; Seraji et al., 2013; McDonald et al., 2013; Tsarfaty, 2013) can be mapped onto the
new taxonomy proposed here. We emphasize the lexicalist
stance of both most work in NLP and the syntactic theoryon which Stanford Dependencies is based, and hence argue
for a particular treatment of compounding and morphology.
We also discuss the different forms of dependency repre-

sentation that should be available for SD to be maximallyuseful for a wide range of NLP applications, converging on
three versions: the basic one, the enhanced one (which adds
extra dependencies), and a particular form for parsing.

2.

A proposed universal taxonomy

Table 1 gives the taxonomy we propose for the universal
grammatical relations, with a total of 42 relations. These
relations are taken to be broadly supported across many languages in the typological linguistic literature.1

2.1.

The representation builds on lexicalism

An under-elaborated part of the first design principle in(de Marneffe and Manning, 2008) is that SD adopts the lexicalist hypothesis in syntax, whereby grammatical relations
should be between whole words (or lexemes). There is alongstanding, unresolved debate in linguistics between theories which attempt to build up both words and phrases
using the same compositional syntactic mechanisms (andin which the notion of a word has minimal privileged existence) versus those theories where the word is a fundamental unit and which see the morphological processes thatbuild up words as fundamentally different from and hidden to those that build up sentences, sometimes termed thelexical integrity principle (Chomsky, 1970; Bresnan andMchombo, 1995; Aronoff, 2007). For a practical computational model, there are great advantages to a lexicalist approach. However, there remain certain difficult cases, suchas how to deal with certain clitics (Zwicky and Pullum,1983), phonologically bound words which behave like syntactic words (we follow many treebanks in separating themas words and having them participate in the syntax) andhow to treat words that are split in unedited writing (seesection 2.4.).
1
This is not to say that all languages have all these grammatical
relations. E.g., many languages, from English to Chicheŵa, allow
verbs to take more than one object, but other languages, such as
French, do not. Nevertheless, iobj is broadly attested.

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
advmodnfincl
neg
nmod
ncmod
Special clausal dependents
Nominal dep
Auxiliary
vocativeaux
discourse
auxpass
expl
cop
Coordination
conj

Other
mark
punct

cc

Noun dependents
Nominal dep
Predicate dep
nummodrelcl
appos
nfinclnmod
ncmod

Modifier word
amod
det
neg

Compounding and unanalyzed
compoundmwe
goeswith
nameforeignCase-marking, prepositions, possessive
case
Loose joining relations
list
parataxis
dislocated
Other
Sentence headroot

remnant
reparandum

Unspecified dependency
depof multiple objects, the theme/patient argument is the direct
object. Finally, the taxonomy aims to clearly indicate in thedependency label (i) a non-canonical voice subject (where
the proto-agent argument is not subject, i.e., in passives)and (ii) whether dependents are noun phrase (NP) arguments versus introducing a new clause/predicate. A design
goal of SD has been to distinguish in dependency names
where a new clause is being introduced (and so we distinguish nsubj and csubj; dobj and ccomp, but also advmod
and advcl). We follow LFG in including a distinction between ccomp and xcomp for clausal complements that are
standalone (have an internal subject) versus those having
necessary control (omission) of the dependent predicate’s
subject (have an external subject).3
Other aspects of the typology are less regular but still
important. The non-core clausal dependents are all modifiers. The distinction between a full adverbial clause advcl
and a participial or infinitive nonfinite clause nfincl is similar but not exactly parallel to the ccomp/xcomp distinction.4
Clause heads have many other special dependents, including periphrastic auxiliaries, markers (complementizers andsubordinating conjunctions) as well as vocatives and discourse elements (like well or um). Conjunctions combine
elements of many categories. Under the SD design principles, the conj relation connects lexical heads.

2.3.

Treatment of copulas

SD has advocated a treatment of the copula “be” where it
is not the head of a clause, but rather the dependent of a lexical predicate, as in (1a). Such an analysis is motivated by
the fact that many languages often or always lack an overt
copula in such constructions, as in the Russian (1b). Similar
constructions arise even in English if we consider so-calledraising-to-object or small clause constructions. Under thebasic analysis proposed for SD, the predicate complement
is not linked to its subject argument, but in the enhanced
representation (see below), the linkage is then parallel tothe treatment in a zero copula language, as in (1c).
nsubjTable 1: Dependencies in universal Stanford Dependencies.
Note: nmod, ncmod, nfincl, and neg appear in two places.

cop
det
amod

(1) a. Ivan

2.2.

Dependents of clausal predicates

The system of clausal dependents most closely follows Lexical-Functional Grammar (LFG) (Bresnan, 2001).
However, the taxonomy differs from LFG in several respects. First, the clear distinction between core arguments
and other dependents is made, but the distinction between
adjuncts and oblique arguments (Radford, 1988) is taken
to be sufficiently subtle, unclear, and argued over that it iseliminated.2 Second, the model reverts to the traditional
grammar notion of direct object and other objects. In cases
2

The original Penn Treebank annotators also decided not to try
to mark arguments vs. adjuncts (Taylor et al., 2003). Conversely,
the Penn Chinese Treebank does try to make an adjunct/argument
distinction (Xue et al., 2005) and effectively PropBank (Palmer
et al., 2005) adds an argument/adjunct distinction overlay to theEnglish Penn Treebank.

3

is

the

best

dancer

The latter is used to represent control and raising constructions, including cases of raising-to-object or so-called “exceptional case marking”. The treatment of this last group of phenomena is one of the largest substantive breaks with the Penn Treebank annotation tradition, which follows Chomskyan approaches
from the extended standard theory, Government-Binding Theory(Chomsky, 1981) et seq., in treating such constructions as having
a complete clausal complement with “exceptional case marking”,
rather than an object in the higher clause.
4
For ccomp vs. xcomp, the defining difference is a controlled
subject. While an xcomp is always non-finite, there are also nonfinite ccomp, such as in a for-to infinitive (“I arranged [for her
to go by bus]”). For advcl vs. nfincl the distinction is a finite
clause vs. a non-finite clause, though usually a reduced one lacking a subject. We generalize the previous partmod and infmod tonfincl for more generality and cross-linguistic applicability. We
use nfincl rather than vmod since this modifier can also be an adjective, as in “She hesitated [unable to remember his name]”.

b. Russian:
nsubj
amod

Ivan
Ivan

lučšij
best

tancordancer
xcomp
nsubj
det

nsubj

c. I

2.4.

dobj

judge

amod

Ivan

the

best

dancerModification vs. compounding

The universal scheme keeps the rich taxonomy of noun
dependents that are one of the strengths of SD. An important part of the typology is to differentiate compounds(multi-root lexemes) from modification or complementation. Under a lexicalist approach, compound words are fundamentally different from cases of phrasal modification.
There are three relations for compounding. We use mwe
for fixed grammaticized expressions with function words(e.g., instead of : mwe(of,instead), Fr. plutôt que “rather
than”: mwe(que,plutôt)), name for proper nouns constitutedof multiple nominal elements, as in the Finnish and Italiandependency treebanks,5 and compound to label other typesof multi-word lexemes. Thus compound is used for any
kind of X0 compounding: noun compounds (e.g., phonebook), but also verb and adjective compounds that are morecommon in other languages (such as Persian or Japaneselight verb constructions); for numbers (e.g., three thousand books gives compound(thousand,three)); for particles
of phrasal verbs (e.g., put up: compound(put,up)).

2.5.

Treatment of prepositions and case marking

A major proposed change from the extant versions of
SD is a new treatment of prepositions to provide a uniform
analysis of prepositions and case in morphologically richlanguages. The analysis we chose is to push all the way
the design principle of having direct links between content words. We abandon treating a preposition as a mediator between a modified word and its object, and, instead, any case-marking element (including prepositions,
postpositions, and clitic case markers) will be treated as adependent of the noun it attaches to or introduces. The proposed analysis is shown in (2): nmod labels the relation
between the two content words, whereas the preposition is
now viewed as a case depending on its complement. In
general, nmod expresses some form of oblique or adjunctrelation further specified by the case.
nmod
det

Chair

(3) a. Hebrew:
dobj
case

wkfraiti
and when I saw’sb. thehsrj
the movie

ACC

b. dobj(wkfraiti/VERB, hsrj/NOUN)
case(hsrj/NOUN, at/PRT- ACC)
c. Russian:
nmod
nsubj

dobj

Ya napisal pis’mo
peromIwrote the letter with a quill
d. nsubj(napisal/VERB, Ya/NOUN - NOM)
dobj(napisal/VERB, pis’mo/NOUN - ACC)
nmod(napisal/VERB, perom/NOUN - INSTR)
This treatment provides parallelism between different
constructions across and within languages. A good result isthat we now have greater parallelism between prepositional
phrases and subordinate clauses, which are in practice often
introduced by a preposition, as in (4).
nmod
case
nsubj

(4) a. Sue

det

left

after

the

rehearsal

advcl
mark
nsubj

nsubj

b. Sue

left

after

we

did

We also obtain parallel constructions for the possessivealternation as shown in (2), for variant forms with case, apreposition or a postposition in Finnish, as shown in (5),and for the dative alternation where the prepositional construction gets a similar analysis to the double object construction, see (6).
nmod

officecase

etsiä
to search

nmod
case

det

at

(5) a. Finnish:case(2) a. theThe treatment of case marking is illustrated in (3). In(3a), at in Hebrew is a separate token indicating an accusative object: the case marker depends on the object. In(3c), we show the analysis when case markers are morphemes. The case morpheme is not divided off the noun
as a separate case dependent, but the noun as a whole isanalyzed as a nmod of the verb. To overtly mark case, we
include POS tags in the representation as shown in (3b) and(3d). We use the universal POS tagset from Petrov et al.
(2012) to which we append case information.

ilman
without

johtolankaa
clue.PARTITIVE

det

office

of

the

nmod

Chair

c. French:b.

etsiä
to searchc.

etsiä
to searchcasetaskulampun
torch.GENITIVE

nmod
det

le
the

nmod

case

bureauofficeduofprésident
the Chair

5

That is, name would be used between the words of “Hillary
Rodham Clinton” but not to replace the usual relations in a phrasal
or clausal name like “The Lord of the Rings”.

johtolangattaclue.ABESSIVE

dobj
iobj

(6) a. give the children the toyskanssa
with

nmod
dobj

case

b. give the toys to the children
c. French:
nmod
dobj

case

donner les jouets aux enfants
give
the toys to the children
Another advantage of this new analysis is that it provides a treatment of prepositional phrases that are predicative complements of “be” as in (7) that is consistent with thetreatment of nominal predicative complements, as in (1).
nsubj
cop
case

(7) Sue

is

in

shape

SD is a surface syntactic representation, which does not
represent semantic roles. The semantic roles of modifiers
are hard to categorize and hard to determine. We feel that
there is a lot of use for a representation which works solely
in terms of the overt role-marking resources of each language. This is supported by many rich language-particular
traditions of grammatical analysis, whether via Sanskrit
cases or the case particles on Japanese bunsetsu.
Prepositions sometimes introduce a clause as their complement, e.g., (8a). Following the principle that dependencies do mark where new clauses are introduced, this relation
should have a different name from nmod, and we suggest
calling it ncmod “nominalized clause modifier”. Under the
proposed new analysis, the head of the modifier of data will
be upset. The result will be the analysis in (8b).

The “loose joining relations” aim at a robust analysis of
more informal forms of text, which are now common in
NLP applications. Informal written text often contains listsof comparable items, which are parsed as single sentences.
Email signatures in particular contain these structures, inthe form of contact information. Following de Marneffe etal. (2013), we use the list, parataxis, (and appos) relations
to label these kinds of structures. The relation parataxis isalso used in more formal writing for constructions such as
sentences joined with a colon.
The dislocated relation captures preposed (topics) andpostposed elements. The remnant relation is used to provide a treatment of ellipsis (in the case of gapping or stripping, where predicational or verbal material gets elided),something that was lacking in earlier versions of SD. It
provides a basis for being able to reconstruct dependencies
in the enhanced version of SD. For example, in (11), theremnant relations enable us to correctly retrieve the subjects and objects in the clauses with an elided verb.
remnant

remnant
remnant

remnant
nsubj

dobj

(11) John won bronze, Mary silver, and Sandy gold.
In contrast, in right-node-raising (RNR) (12) and VPellipsis (13) 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 theauxiliary as the head, as shown in (13).
dobj
conj
nsubj

(8) a. We have no data about whether users are upset.
ncmod
case

conj

mark

nsubj

nsubj
cop

Another issue is what analysis to give to cases of stacked
prepositions, such as out of. Our proposal is that all suchcases should be regarded as some form of mwe, as in (9b).
(9) a. Out of all this, something good will come.
caseb. Out2.6.

nmod

predet

of

all

this

...

come

Informal text genres

Following the practical approach used in part-of-speechtagging of recent LDC treebanks, we introduce the relation
goeswith to connect multiple tokens that correspond to asingle standard word, as a result of reanalysis of words ascompounds (“hand some” for “handsome”) or input error(“othe r” for “other”). We use foreign to label sequencesof foreign words. To indicate disfluencies overridden in aspeech repair, we use reparandum, as in (10).
nmod
reparandum
case

case
det

(10) Go

to

the

det

righ-

to

the

cc
aux

(13) Johnb. data about whether users are upset

mwe

cc

(12) John bought and ate an apple.

left.

2.7.

will

dobj

win

gold

nsubj

and

Mary

advmodwill

too.

Language-particular relations

In addition to a universal dependency taxonomy, it is desirable to recognize grammatical relations that are particular to one language or a small group of related languages.
Such language-particular relations are necessary to accurately capture the genius of a particular language but will
not involve concepts that generalize broadly. The suggestion here is that these relations should always be regarded
as a subtype of an existing Universal SD relation. The
SD relations have a taxonomic organization (de Marneffe
et al., 2006), and some of the universal relations are already subtypes of each other (e.g., auxpass is a subtype ofaux). Language-particular relations that seem useful to distinguish for English are included at the bottom of Table 2:
npmod for bare nominal modifiers of predicates lacking a
preposition, among which in particular there is tmod forbare NP temporal modifiers; poss for possessives, since thesyntax of prenominal possession is very distinct from postnominal modifiers (which may also express possession);predet for words such as all that precede regular determiners and preconj for words preceding a conjunction like either; and prt for verb particles.

3.

Mapping to existing schemes

There has recently been an effort to push towards homogeneity across resources for different languages andto come up with cross-linguistically consistent annotation
aimed at multi-lingual technology, for part-of-speech tagset(Petrov et al., 2012) as well as for dependency representation (McDonald et al., 2013). The scheme proposed in McDonald et al. (2013) took SD as a starting point. Annotators for six different languages (German, English, Swedish,Spanish, French and Korean) produced annotation guidelines for the language they were working on, keeping thelabel and construction set as close as possible to the original
English SD representation. They were only allowed to add
labels for phenomena that do not exist in English. Given thesets of relations obtained for the different languages, a harmonization step was performed to maximize consistency ofannotation across languages. However, this rigid strategy
lost some important distinctions, such as the distinction between compounding and phrasal modification, while maintaining some distinctions that are best abandoned, such as a
distinction between infinitival and participial modifiers.
McDonald et al. (2013) does not address giving an elegant treatment of morphologically rich languages. In contrast, Tsarfaty (2013) proposes to treat morphology as syntax in her dependency proposal, illustrated with Hebrew.
However, this representation choice conflicts with the lexicalist approach of SD. Here we take up her goal of trying
to give a uniform treatment of both morphologically richand morphologically poor languages, but suggest achieving
the goal in a different way, which maintains a lexicalist approach (see Section 2.5.). Table 2 shows a comparison between the evolution of the SD scheme (Stanford Dependencies v2.0.0, used in the SANCL shared task, and Stanford
Dependencies v3.3.0, the 2013/11/12 version), the proposals in McDonald et al. (2013) (GSD) and in Tsarfaty (2013)(TSD), and the dependency set proposed here (USD).
Existing dependency sets for other languages can be
fairly straightforwardly mapped onto our new proposal.
Even if the schemes examined here are “SD-centric”, they
dealt with particular constructions present in each language
and posited new relations when necessary. The mapping isless difficult because USD adopts some of the ideas and relations that were first developed for these other treebanks,
such as the content word as head analysis of prepositional
phrases from the Turku Dependency Treebank (TDT). In
table 3, we show how the Finnish (Haverinen et al., 2013),
Italian (Bosco et al., 2013), Chinese (Chang et al., 2009)
and Persian (Seraji et al., 2013) schemes can be mapped
onto the proposed universal taxonomy (USD). The bold labels are language-specific relations, and they are subtypesof the corresponding USD relation in the row. Gaps indicate existing constructions in the language that were notcaptured in the original scheme (the USD label is applicable
there); ∗ indicates constructions that are not present in thelanguage. Since copular verbs are not heads anymore, theattr relation is removed, requiring modifications to the existing analyses of copular sentences for Italian and Chinese.
We also introduced extra relations for certain constructions,which some schemes had not incorporated yet.
For Finnish, the relation rel (for relative marker) will bemapped to whatever syntactic role the relative is playing in
the relative clause (nsubj, dobj, etc.), information which ispresent in the second annotation layer of the TDT corpus.
ISDT is the conversion of the MIDT Italian dependency
scheme to SD. Some of the clit uses in ISDT (for reflexive pronouns in pronominal verbs – frequent in Romance
languages – such as Fr. se douter “to suspect”) will be encompassed by expl. However, when the reflexive pronoun
can truly be a direct or indirect object, it gets assigned thecorresponding object relation.
Chinese has serial verb constructions which might now
be compound (and not conj). We treat post-nominal localizers and prepositions as a form of case.
In Persian, there are no relative pronouns and rel wasused for the fixed relative marker, but it can be mapped tomark. UPDT has a fw relation between sequences of foreign words, unanalyzed within Persian grammar, which weadopt, naming it foreign. We also adopt the UPDT dep-top
relation used for a fronted element that introduces the topic
of a sentence, but we generalize it to dislocated to accountfor postposed elements as well as. Right dislocated elements are frequent in spoken languages: e.g., Fr. faut pas
la manger, la pâte (literally, “need not it eat, the dough”).
Labels of language-specific relations will be harmonized
to be shared between languages: Chinese assmod will bemapped to poss, and Persian dep-top to topic.

4.

Different forms of Stanford Dependencies

The current Stanford converter provides a number ofvariant forms of SD, of which the most used are the basic dependency tree, and the collapsed, cc-processed form
that adds extra dependency arcs, restructures prepositions
to not be heads, and spreads relations across conjunctions.
This section suggests some new ideas for how to provide
potentially less but different options.
One concern about our proposed taxonomy is thatstraightforward parsing to USD is likely to be harder forparsers than the current representation (for English). It
is now fairly well known that, while dependency representations in which content words are made heads tend
to help semantically oriented downstream applications, dependency parsing numbers are higher if you make auxiliary
verbs heads, if you analyze long conjunctions by chaining(rather than having a single head of the whole construction),and if you make prepositions the head of prepositional
phrases (Schwartz et al., 2012; Elming et al., 2013). The
generalization is that dependency parsers, perhaps in particular the efficient shift-reduce-style dependency parsers
like MaltParser (Nivre et al., 2007), work best the more thedependency representation looks like a chain of short dependencies along the sentence. Under the proposed USD,
SD would then be making the “wrong” choice in each case.
However, it seems wrong-headed to choose a linguistic representation to maximize parser performance, rather
than based on the linguistic quality of the representationand its usefulness for applications that build further processing on top of it. Rather, it may be useful to do parsing using a transformation of the target dependency system. In constituency parsing, it is completely usual for thetarget representation to be transformed so as to improve

SD v2.0.0

SD v3.3.0

GSD

TSD

USD

Notes

nsubj
csubj
nsubjpass
csubjpass
dobj
iobj
ccomp
xcomp
acomp
attr

nsubj
csubj
nsubjpass
csubjpass
dobj
iobj
ccomp
xcomp
acomp
–

nsubj
csubj
nsubjpass
csubjpass
dobj
iobj
ccomp
xcomp
acomp
attr

nsubj
csubj
nsubjpass
csubjpass
dobj
iobj
ccomp
xcomp
acomp
–

nsubj
csubj
nsubjpass
csubjpass
dobj
iobj
ccomp
xcomp
–
–

X
X
X
X
X
X (TSD also has gobj for genitive object)
USD & TSD define as clause with internal subject, not finite
USD & TSD define as clause with external subject, not nonfinite
acomp can be generalized into xcomp
attr removed: wh- is head or xcomp (with copula head option)

advmodadvcl
purpclneg

advmodadvcl–
neg

advmodadvcl–
neg

advmod––neg

advmod
advcl
–
neg

X
TSD omits but needed to preserve clause boundaries
Folded into advcl
As well as adverbial not, never, USD extends to negative det like no

det
amod
appos
abbrevnum
rcmod
partmod
infmodquantmod

det
amod
appos
–
num
rcmod
partmod
infmodquantmod

det
amod
appos
–
num
rcmod
partmod
infmodadvmod

det
amod
appos
abbrevnummodrcmod?
infmod
?

det
amod
appos
–
nummodrelcl
nfinclnfincl–X (TSD defines dem and def as subtypes of det)
X
X
Parenthetical abbreviations become cases of appos
Renamed for clarity
X
Make partmod, infmod into nfincl; use (rich) POS to distinguish
Make partmod, infmod into nfincl; use (rich) POS to distinguishGenerally folded into advmod

root
punct
aux
auxpass
cop

root
punct
aux
auxpass
cop

ROOT
p
aux
auxpass
cop

root
punct
aux
auxpass
cop

root
punct
aux
auxpasscop

X (TSD adds qaux for question auxiliary. Infinitive is now mark.)
X
GSD has cop only in content-head version

expl
mark
complm
–
–
dep
rel

expl
mark
–
discourse
–
dep
–

expl
mark
–
–
–
dep
rel

expl
mark
complmparataxis?
–
dep
rel

expl
mark
–
discourse
vocative
dep–

Subject and object expletives, frozen reflexives (Fr. se douter)
X to introducing an infinitive will now be mark (instead of aux)
Remove and use mark more broadly
A gap in original and other typologies
A gap in original and other typologies
GSD uses for vocative and discourse
Converter’s unresolved ones now dep; TSD rel is really mark

prep
–
pobj
pcomp

prep
–
pobj
pcomp

adpmodnmod
adpobjadpcompprepmod
–
pobj
pcomp

case
–
nmod
ncmod

USD case is dependent of NP modifier not of thing modified
Equivalent to nmod below
nmod now goes from thing modified to NP of PP
ncmod goes from thing modified to clause–possessive–
possessive

adp
adp

prep/case
gen

case
–

TSD has N/A/G/D subtypes, but can’t keep adding for all cases
View as a manifestation of casenn–number
mwe
–
–
–

nn
–
numbermwe
goeswith––

compmod
mwe
num
mwe
–
–
–

nn
–
nummod?
mwe–––

compoundname–mwegoeswith
foreign
reparandum

Generalize nn to light verbs, etc.; X0 compounding not modification
Multi-word proper nouns (e.g., John Smith) as in TDT and ISDTRegarded as type of compound; using nummod is wrong
Fixed expressions with function words (so that, all but, due to, . . . )For orthographic errors: othe r
Linear analysis of foreign words (head is left-most) as in UPDTFor disfluencies overridden in speech repairs

conj
cc

conj
cc

conj
cc

conj
cc

conj
cc

X
X

parataxis–––

parataxis–––

parataxis–––

parataxis–––

parataxis
list
remnant
dislocated

X
Used for informal list structures, signature blocks, etc.
Used to give a treatment of ellipsis without empty nodes
Preposed topics and dislocated elements as in UPDTEnglish particular
npadvmod npadvmod
tmod
tmod
predetpredetpreconj
preconj
prt
prt
poss
poss

nmod
advmod
–
cc
prt
poss

advmod?
tmod
predetpreconj?
possmod

npmod
tmod
predetpreconjprtposs

A subtype of nmod
A subtype of npmod
A subtype of det
A subtype of cc
A subtype of compound
A subtype of case

Table 2: Comparison of proposals on English: SD, McDonald et al. (2013) (GSD), Tsarfaty (2013) (TSD) and ours (USD).

TDT

ISDT

Chinese

UPDT

USD

nsubj
csubj
∗
∗
dobj
∗
ccomp, iccomp
xcomp, acomp
∗

nsubj
csubj
nsubjpass
csubjpass
dobj , clit
iobj , clit
ccomp
xcomp, acomp
attr

nsubj, top

attr

nsubj
∗
nsubjpass
∗
dobj
∗
ccomp
xcomp, acomp
∗

nsubj
csubj
nsubjpass
csubjpass
dobj
iobj
ccomp
xcomp
∗

advmod, quantmod
advcl
neg

advmodadvcl
neg

advmod, dvpmod
some advmod
neg

advmod, quantmod
advcl
neg

advmod
advcl
neg

det
amod
appos
num
rcmod
partmod, infmod

det, predet
amod
appos
num
rcmod
partmoddet
amod
prnmodnummod, ordmod
rcmod
vmod

det, predet
amod
appos
num
rcmod
∗

det
amod
appos
nummodrelcl
nfincl

root
punct
aux
auxpass
cop

root
punct
aux
auxpass
cop

root
punct
asp, mmod
pass
cop

root
punct
aux
auxpass
cop

root
punct
aux
auxpass
cop∗complm, mark
intj
voc
dep

expl, clit
mark
discourse∗
cpm∗
complm, mark, relcomp, moddep

dep-voc
dep

expl
mark
discourse
vocativedep

poss, gobj, gsubj,
nommod∗adpos
number, nn, prt
namesome dep

pobj, poss,
npadvmod, tmod
pcomp
possessive, prep
number, nn
nnp
mwe
goeswith

pobj, lobj, assmod,
clf, range, tmod
pccomp, lccomp
assm, prep, ba, dvpm, loc
nn, some conj

pobj, poss, cpobj
npadvmod, tmod∗
acc, prep, cprep
number, nn, prt, {nsubj|dobj|acomp|prep}-lvc

prtmodmwe

nsubjpass
dobj
iobj
ccomp, rcomp

fw
conj
cc, preconj
parataxis

conj
cc, preconj
parataxis

conj, etc, comodcc

conj
cc, preconjunctparataxis

ellipsis
dep-top

nmod
ncmod
case
compoundnamemwegoeswith
foreign
reparandum
conj
ccparataxis
list
remnant
dislocated

Table 3: Mappings of the Finnish (TDT), Italian (ISDT), Chinese and Persian (UPDT) schemes to USD.
parsing numbers, such as by head-lexicalization (Collins,
2003), by manual or automatic subcategorization of categories (Klein and Manning, 2003; Petrov et al., 2006),
and even by other methods such as unary chain contraction (Finkel et al., 2008). After parsing, a detransformation
process reconstructs trees in the target representation. Thiskind of transform-detransform architecture is at present lesscommon in dependency parsing, although Nilsson, Nivre& Hall (2006; 2007) do this for coordination and verb
groups, and pseudo-projective parsing (Nivre and Nilsson,2005) can also be seen as an instance of this architecture.
A transform-detransform architecture should become more

standard in dependency parsing. We therefore propose aparsing representation that changes some of the dependency head choices to maximize parsing performance. Thisrequires developing tools to convert seamlessly both ways
between the basic and parsing representations.6
Since the new treatment of prepositional phrases basically does what the collapsed representation was designed
to do (putting a direct link between the noun complement ofa preposition and what it modifies), except for not renaming
6

A small part of this is in place in the Stanford converter, in theability to generate copula- and content-head versions from trees.

the dependency relation, the collapsed representation on its
own has less utility. However, the ideas of having extra dependencies to mark external subjects and the external role
in relative clauses is useful, the renaming of dependencies
to include case or preposition information helps in many
applications, and spreading relations over conjunctions isdefinitely useful for relation extraction. These transformations can be provided in an enhanced representation.
We thus suggest providing three versions of Stanford Dependencies: basic, enhanced, and parsing.

5.

Conclusion

We proposed a taxonomy of grammatical relations applicable to a variety of languages, developing the implicationsof a lexicalist approach for the treatment of morphology
and compounding. Some of the decisions made on linguistic grounds are at odds with what works best for processing
tools. We suggested that the transform-detransform architecture standardly used in constituency parsing is the solution to adopt for dependency parsing. We worked out the
mapping of existing dependency resources for different languages to the taxonomy proposed here. We hope this work
will enhance consistency in annotation between languages
and further facilitate cross-lingual applications.

6.

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