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Sign Language Grammar and Typology (SiLaGaT)

Sign Language Grammar and Typology



  • Prof. Enoch Aboh (ACLC), senior researcher
  • Prof. emeritus Anne Baker (ACLC), senior researcher
  • Eveline Boers-Visker (ACLC), PhD candidate on external project (in cooperation with Utrecht University of Applied Sciences) “Learning to use space: a study into the SL2 acquisition process of adult learners of Sign Language of the Netherlands” (since March 2016)
  • Prof. emeritus Beppie van den Bogaerde (ACLC), senior researcher
  • Cindy van Boven (ACLC), PhD candidate NWO ‘Promoveren in de Geesteswetenschappen’, project “Morphological reduplication in Sign Language of the Netherlands: A typological and theoretical perspective”, September 2019 – August 2023
  • Ulrika Klomp (ACLC), PhD candidate on Pfau’s Horizon2020 project SIGN-HUB, subproject “A descriptive grammar of Sign Language of the Netherlands”, July 2016 – June 2020
  • Vanja de Lint (ACLC), PhD candidate on Pfau’s NWO Free Competition project, subproject “Argument structure in Sign Language of the Netherlands”, September 2015 – August 2020
  • Marloes Oomen (ACLC), PhD candidate on Pfau’s NWO project, subproject “Argument structure in German Sign Language”, September 2015 – August 2019
  • Dr. Roland Pfau (ACLC), senior researcher, coordinator
  • Dr. Beyza Sümer (ACLC), senior researcher


Comparative studies on languages of different language families have revealed striking differences as well as interesting (possibly universal) similarities concerning their grammatical – in particular, morphological and syntactic – structure. However, traditionally, these studies were only concerned with the comparison of grammatical phenomena across spoken languages. Once we include sign languages in the typological picture, new research questions emerge.

First of all, we need to ask whether grammatical models that have been developed on the basis of spoken language data can also be applied to sign languages. The general picture that emerges is that many of these models are in fact applicable to visual-gestural languages. While studies that test the cross-modal applicability of theoretical models often focus on a single sign language, it is also important to include, in a second step, typological comparisons in the investigation. On the one hand, we want to know whether typological classifications and generalizations that have been established on the basis of spoken language samples also hold for sign languages despite the different language modality. In case we find modality-specific patterns, we need to investigate whether these can be accounted for in a theoretical model. On the other hand, we also want to know in how far sign languages differ from each other. And even more importantly: do they differ along the same lines as spoken languages do?

Mailing List
If you want to be put on the mailing list of the SiLaGaT research group, please send an email to Roland Pfau.

Research highlights in 2019

In the study of South African Sign Language, Anne Baker, together with colleagues from the University of Stellenbosch and the National Institute for the Deaf, studied the historical roots of South African Sign Language. Variation in SASL and in the potential source languages was taken into account. The SASL sign types were compared with counterparts in six potential lexifier sign languages, American Sign Language (ASL), British Sign Language (BSL), Irish Sign Language (ISL), German Sign Language (DGS), Flemish Sign Language (VGT), and Sign Language of the Netherlands (NGT), as well as the Paget-Gorman Sign System (PGSS). Signs that are heavily influenced by iconic devices were removed from the final comparison. Loan signs were identified on the basis of phonological similarity. The highest percentage of borrowings was from BSL at 15.9%, followed by ASL with 12.6% and VGT at 11.7%; 65.4% of the sign types were influenced to some degree by foreign sign languages or PGSS. There is a substratum of signs that did not match with any of the potential lexifier languages or PGSS and their origins are uncertain; they possibly emerged naturally or were borrowed from a language that was not included in this study.

Eveline Boers-Visker continued the investigation of how novel learners of Sign Language of the Netherlands (NGT), whom she followed over a period of two years, acquire spatial devices, in particular classifier predicates and agreement verbs. She describes empirical evidence which suggests that learners use their gestural knowledge to bootstrap their NGT acquisition: since classifier predicates have gestural cognates, they are acquired earlier than agreement verbs. She proposes that novel learners recognize classifier predicates earlier in the teacher output than agreement verbs. In a follow-up study, she investigated whether learners benefit from explicit grammatical instruction regarding agreement verbs. Results from her experimental study indicate that both learners who received explicit instruction and learners who received an implicit input flood performed better on the post-test than a control group. She hypothesizes that this rather unexpected result might be the result of the visual modality.

Beppie van den Bogaerde and Anne Baker studied the rules of turn-taking when signing, such as the extent to which overlap is allowed and when, and which attention strategies are used by signers when overlapping. This topic was investigated by comparing the more complex triadic situation (involving three people) of a deaf mother and her two deaf twins aged 5;6 years, together with how the adult communicated with these two children individually. Visual attention for the beginning of utterances was mostly established, but more so in the dyadic than the triadic situation. Seating position appeared to be relevant. More explicit strategies to attract eye-gaze were used in the triadic than the dyadic situation, including less usual strategies. Despite the conversation being between three people and needing checks with all participants, there was not more overlap in the triadic situation. Development in turn-taking is clearly still continuing after age six years.

In collaboration with Door Spruijt, Cindy van Boven described in detail the marking of imperative sentences in Sign Language of the Netherlands (NGT), including negative imperatives. They found that NGT marks the imperative by means of manual markers, non-manual markers, and subject omission. While affirmative imperatives are always marked by at least one of these features, none of them is obligatory. Negative imperatives, on the other hand, do display obligatory and systematic marking. Cindy also analyzed plural nouns in the Corpus NGT. Her corpus search revealed four plural marking strategies: simple reduplication, sideward reduplication, simultaneous reduplication, and zero marking. The results suggest that the choice between these strategies depends – to some extent – on phonological properties of the base noun.

Ulrika Klomp found, based on an analysis of corpus data, that the lexical NGT verb COME has undergone grammaticalization, thereby gaining two grammatical functions: a marker of future tense and a marker of change of state. When COME functions as one of these markers, it usually appears before the predicate. Additionally, she re-analyzed previously collected data on the potential use of GO as a future tense marker and concluded that GO does not mark future tense in NGT. In context of the descriptive NGT grammar she is writing, she further conducted corpus research on alternative interrogatives. The data reveal that this question type can be marked by three different strategies, none of which is obligatory.

Marloes Oomen finished her dissertation on verbs in German Sign Language, in which she offers a novel solution to the typological puzzle that in many sign languages supposedly only verbs of a (partially) semantically definable subset agree. Based on an analysis of a range of semantic and morphosyntactic properties of different verb types – where iconicity is demonstrated more than once to play a mediating role – she comes to the conclusion that even ‘plain’ verbs, in fact, grammatically agree with their arguments, motivating a unified syntactic analysis in terms of agreement. In October 2019, Marloes was awarded a prestigious Niels Stensen Fellowship grant for a one-year postdoctoral project, to be carried out at Institut Jean Nicod in Paris.

Roland Pfau, together with Ulrika Klomp and Marloes Oomen, continued a project that aims at providing a detailed description of negation in Sign Language of the Netherlands. They presented the first in-depth study of negative transport in a sign language, that is, a constructions type in which negation in the matrix clause is interpreted in the embedded clause; cf. English “I don’t think he will win”, which actually means “I think he will not win”. They found (i) that negative transport exists in NGT, (ii) that it is confined to certain (cognitive) predicates, just as in spoken languages, and (iii) that negative transport constructions display characteristic patterns of headshake spreading, different from constructions involving non-negative transport predicates (e.g., “I don’t say he will win”). Marloes will further investigate this intriguing construction type in the context of her fellowship.

Investigating language acquisition from a multimodal perspective, Beyza Sümer, together with Aslı Özyürek (RU, MPI & Donders), found that signing and speaking children acquire topological spatial relations (e.g., in, on, under) at a similar pace despite the iconic linguistic forms available to signing children. This shows the primacy of cognition, rather than language modality (i.e., sign vs. speech) in acquiring spatial relations in one’s language. In another project with Dilay Karadöller (RU & MPI) and Aslı Özyürek, they found that signing children who have been exposed to Turkish Sign Language at around 8 years of age and late signing deaf adults differed from native signers (i.e., signers who have been exposed to Turkish Sign Language since birth) in their use of linguistic devices for view-dependent relations (e.g., left, right) but not in their use of devices for topological spatial relations (e.g., in, on, under). Together with Francie Manhardt (RU & MPI), Aslı Özyürek (RU, MPI, & Donders), Dilay Karadöller (RU & MPI), and Susanne Brouwer (RU), Beyza has also been involved in a project in which they investigated the eye-gaze patterns of deaf NGT signers in comparison to Dutch speakers while describing the location of objects (e.g., pen left to paper). They found that during message preparation, signers, but not speakers, experienced increasing eye-gaze competition from other spatial configurations as well as the target one.

Current external funding

218.648 Euro from European Commission, Horizon 2020 (Reflective Society) project “SIGN-HUB: preserving, researching and fostering the linguistic, historical and cultural heritage of European Deaf signing communities with an integral resource” (grant agreement number 693349);

174.987 Euro from NWO Promoveren in de Geesteswetenschappen, project “Morphological reduplication in Sign Language of the Netherlands: A typological and theoretical perspective” (grant number PGW.19.003).


  • Members of the research group maintain a Facebook page (with approx. 680 subscribers) on which information related to sign language is posted, often in NGT with subtitles (research results, conference reports, and announcements).
  • The SiLaGaT group interacted closely with the Hogeschool Utrecht in the context of the Horizon2020 project, the Leverhulme project, and in the context of a joint PhD project on second language acquisition of NGT. The three projects are relevant (i) for improving the status of NGT, (ii) for improving language teaching for future interpreters and teachers, and (iii) for the dissemination of knowledge in academia and in the professional field.
  • Anne Baker is collaborating with colleagues from South Africa, specifically from the National Institute of the Deaf, in putting together a dictionary of South African Sign Language that will be freely available to users.
  • Furthermore, Anne Baker, together with colleagues working at South African schools for the Deaf, is involved in the development of a Sentence Repetition Task to assess children’s ability in South African Sign Language.
  • Roland Pfau taught three courses on sign language linguistics and typology in Brazil: in Maceio (May 2019), Parnaiba and Araraquara (November 2019). All three courses were free of charge for participants, and Brazilian Sign Language interpreting was provided. They were thus fully accessible to deaf students, and in fact, approx. half of the 30-40 attendees at each course were deaf.
  • At the conference on the occasion of the 25th anniversary of the European Center for Modern Languages (ECML), Beppie van den Bogaerde and colleagues from the PRO-SIGN2 project presented a unique document on sign language teacher competences for developing curricula for sign language teachers. Furthermore, the new modality-neutral version of the companion volume to the CEFR was presented, with contributions by the PRO-SIGN2 team.
  • Ulrika Klomp presented on the aim and current status of the descriptive grammar of NGT at the NOAP-dag, an annual event at which senior and junior members of the ACLC convene to learn more about each other's work.
  • In the context of the Horizon2020 project SIGN-HUB, Roland Pfau continued the collaboration with De Gelderhorst, a center for elderly deaf people in Ede. The societally relevant goal of the project is the documentation of the cultural and linguistic heritage of this population by means of semi-structured interviews.
  • An important valorization activity of the SIGN-HUB project is the publication of an open access article on the importance of sign language archives for the cultural and linguistic heritage of Deaf communities, authored by Roland Pfau in collaboration with other project members.