Research Interests
  • Acquisition of syntactic structures.
  • Relationship between production and comprehension in child language.
  • The effects of processing and working-memory limitations in language development.
  • Word segmentation by monolingual and bilingual infants.
  • Cross-linguistic differences in language acquisition.
  • Romance languages (particularly Catalan and Spanish).
Current and Past Projects

On the Acquisition of the Unaccusative-Unergative distinction in Spanish (with Laurel Perkins and Nina Hyams)

Over the years, research on the acquisition of grammar has converged on the finding that Italian-and French-speaking children establish the properties of the unergative (agent subjects, e.g., run, sneeze, yell) vs. unaccusative (patient subjects, e.g., fall, melt, die) distinction by the beginning of the two-word stage. In these two languages, children have direct overt evidence of the different verb types because they select different auxiliaries (have vs. be). In Spanish, the distinction is more subtle. It has been claimed that Spanish unaccusative verbs allow post-verbal subjects in broad focus declaratives (Llegó la profesora), while unergatives do not (e.g., *Gritó la profesora). However, whether this or other cues are sufficiently reliable in young children's input to create these two distinct categories is still an open question. We are currently collecting and analyzing corpus data from adults and children (aged 0-6) to examine this question.


On the Acquisition of Spanish wh-questions with Psych Predicates

In Spanish, Class III psychological predicates like ‘gustar’ ('like,' 'please') project a different syntactic structure than most other predicates: The ‘object’ of this psych verb (i.e., dative experiencer) is generated in a higher syntactic position than the ‘subject’ (i.e., nominative theme with which the verb agrees), e.g., A la maestra le gustan los niños (lit. to the teacher 3dat please the children, 'The teacher likes children'). The surprisingly little research there is on children’s acquisition of 'gustar' did not aim to test intervention effects and is inconclusive with regards to whether children have any difficulties with this verb at all. The hypothesis I aimed to test is that children should have significantly more difficulties producing and comprehending sentences with subject (Theme) extraction than object (Experiencer) extraction due to intervention and this verb's structural idiosyncrasy. 

An exhaustive study of all the Spanish-speaking corpora on CHILDES examined the proportion with which children below the age of 7 produce the order Experiencer-gustar-Theme as opposed to Theme-gustar-Experiencer compared to adults. Results show that while both children and adults produce Experiencer-first utterances more so than Theme-first utterances,  children do so to a significantly higher degree than adults (p < .001), in line with intervention accounts, and counter to pure input frequency-based accounts which may have predicted a preference for the canonical SVO (Theme-gustar-Experiencer) order.

I followed up with an experimental study that tested Spanish-speaking children aged 4-6 on d-linked wh-questions with psych verbs like 'gustar' as well as actional predicates that select a superficially similar PP object, such as 'gritar' ('yell'). I predicted that object-extracted questions such as 'A qué niña le gusta la maestra?' ('What girl likes the teacher?') would obtain higher accuracy scores than subject-extracted questions such as 'Qué niña le gusta a la maestra?' ('What girl does the teacher like?'), i.e., we would observe an object>subject asymmetry. Conversely, object-extracted questions with actional verbs, such as 'A qué niña le grita la maestra?' ('What girl does the teacher yell at?') should obtain lower accuracy scores than object-extracted questions such as 'Qué niña le grita a la maestra?' ('What girl yells at the teacher?'), as is often reported in the literature. Our results corroborated this prediction (both p < .001). Furthermore, mismatching number features between the extracted wh-element and the intervening DP ameliorated children's performance in intervening structures only. These results cannot be accounted for on the basis of frequency effects and are most in line with intervention accounts such as featural Relativized Minimality (Rizzi, 2004).

Parts of this study were presented at LSRL 51 in Urbana-Champaign, IL, on April 29-May 1, 2021 and BUCLD 46 in Boston, MA, on November 4-7, 2021.

Sluicing + Rel. Clauses
Sluicing in Early Grammars: Evidence of Syntactic Intervention (with Nina Hyams)

Part I. Sluicing: Identity Condition and Intervention

This study investigates the acquisition of sluicing, i.e., sentence ellipsis, in English to assess if three- to six-year-old children are able to comprehend sluiced sentences in an adult-like manner. We used a wh-question task in which children were asked to answer questions about an image, e.g., ‘I can see the girl is chasing someone, can you see who <the girl is chasing _>?’. We find three- to six-year olds are fully capable of reconstructing the antecedent of ellipsis and respect the identity condition. Interestingly, children performed significantly worse in the object-extracted sluices (e.g., 'I can see Ben is spraying someone, can you see who <Ben is spraying __>') than the subject-extracted sluices (e.g., 'I can see someone is spraying Ben, can you see who <__ is spraying Ben>'). We hypothesize this is due to intervention effects. This study thus contributes to theories on the acquisition of ellipsis and also to the theoretical debate about the syntactic status of the elided material. Parts of this study were presented at GALA 13, in Palma de Mallorca, Spain, in September 7-9, 2017, and BUCLD 42, in Boston, MA, in November 3-5, 2017.

Part II. Sluicing and Relative Clauses: Intervention, Frequency, and Animacy effects

This study tests children’s comprehension of relative clauses (e.g., 'Point to the boy that the girl is pushing _') and sluiced wh-questions (e.g., 'The girl is pushing someone, can you see who <she is pushing_>?'). We find that children do better with subject than with object RCs, arguably due to intervention, and also with subject- as opposed to object-extracted sluices, consistent with analyses that posit structure at the ellipsis site. Moreover, children do better when subject and object mismatch in animacy (e.g., the boy / the train), but only with object-extracted sentences. We conclude frequency plays a role, but we cannot do without structure-based approaches to intervention and submit that [animacy] should be included in the computation of intervention. Parts of this study were be presented at NELS 49 at Cornell University, NY, October 5-7, 2018, BUCLD 43 in Boston, November 2-4, 2018, and LSA 2019 in New York, January 3-6, 2019.

Part III. Sluicing in Mandarin Chinese

In Mandarin, sluice-like strings (‘S-strings’) with argument wh-remnants require the presence of shi, a form that is ambiguous between a copula and a focus marker. We argue for a hybrid analysis of Mandarin S-strings as having two possible derivations, a sluice and a pseudo-sluice, unless one of the structures is independently forced. When shi is a copula, the S-string has a pseudo-sluice analysis, [pro be wh-phrase], involving neither movement nor ellipsis. When shi is a focus marker, the S-string is derived by focus movement followed by TP-ellipsis yielding a sluice analysis. Results from a comprehension experiment with 59 Mandarin-speaking children show that 3-4-year-olds have only a pseudo-sluice/copula analysis of S-strings. They acquire the sluice/focus movement derivation at approximately age 5 at which point they show the “subject advantage” typically associated with A’-movement structures in young children.


  • Liu, Minqi, Nina Hyams, & Victoria Mateu. (in press). The syntax and acquisition of Mandarin sluice-like constructions. Theoretical and Experimental Linguistics

  • Mateu, Victoria & Nina Hyams. (2021). Structural intervention effects in the acquisition of sluicing. Language Acquisition 28. 6-38. [pdf]

  • Liu, Minqi, Nina Hyams, & Victoria Mateu. (2020). Late intervention effects in the acquisition of Mandarin sluice-like constructions.  Proceedings of the 44th Boston University Conference on Language Development [BUCLD 44]. 322-335. Somerville, MA: Cascadilla Press..

  • Mateu, Victoria & Nina Hyams. (2020). The structure of silence: A look at children’s comprehension of sluicing. Proceedings of the 49th Annual Meeting of the North East Linguistics Society [NELS 49]. Volume 2. 265-278. Independently published. [pdf]

  • Mateu, Victoria, Nina Hyams & Lauren Winans. (2019). Intervention effects in early grammar: Evidence from sluicing. Proceedings of the 42nd Boston University Conference on Language Development [BUCLD 42].  532-545. Somerville, MA: Cascadilla Press. [pdf]

  • Hyams, Nina, Victoria Mateu, Lauren Winans. (2017). Ellipsis meets wh-movement: Sluicing in early grammar. In Nicholas LaCara, Keir Moulton & Anne-Michelle Tessier (eds.) A Schrift to Fest Kyle Johnson. Linguistics Open Access Publications. 1. [link]

Experimental Methodologies
Improving practices in developmental research (with The ManyBabies Consortium)

Part I. Infant-Directed Speech Preferences in Monolingual infants

The field of psychology has become increasingly concerned with issues related to methodology and replicability. Infancy researchers face specific challenges related to these concerns. We report on a large-scale, multi-site study aimed at 1) assessing the overall replicability of a single theoretically-important phenomenon and 2) examining methodological, situational, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS) was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three commonly-used infant discrimination methods (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35 [0.29 - 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native language experience, and testing procedure.

Part II. Infant-Directed Speech Preferences in Bilingual infants

This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants’ IDS preference. As part of the multi-lab ManyBabies project, we compared lab-matched samples of 333 bilingual and 385 monolingual infants’ preference for North-American English IDS. Those infants were tested in two age groups: 6–9 months and 12–15 months. We  found that bilingual and monolingual infants both preferred IDS to ADS, and did not differ in terms of the overall magnitude of this preference. However, amongst bilingual infants who were acquiring North-American English (NAE) as a native language, greater exposure to  NAE was associated with a stronger IDS preference, extending the previous finding from MB1 that monolinguals learning NAE as a native language showed a stronger preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes a similar contribution to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments.

Part III. Visual Preference Methodologies at Home

In this collaborative effort, we seek to develop a remote (online) testing framework that can be used across a range of home environments in a wide array of countries. Recruiting children in their homes can alleviate problems of high recruitment costs, since the burden for caregivers is smaller compared to a campus visit. Researchers can therefore potentially access larger, more diverse sample sizes, repeat experimental sessions, and assess test-retest reliability. Our initial focus is on developing a visual preference paradigm, as it is the main dependent variable of many child studies.


  • Visser, Ingmar et al. (in press). Improving the generalizability of infant psychological research: The ManyBabies model. Behavioral and Brain Sciences.

  • The ManyBabies Consortium (2021). A multi-lab study of bilingual infants: Exploring the preference for infant-directed speech. Advances in Methods and Practices in Psychological Science. 4(1). 1-30. [pdf]

  • The ManyBabies Consortium. (2020). Quantifying sources of variability in infancy research using the infant-directed speech preference. Advances in Methods and Practices in Psychological Science 3(1). 24-52. [pdf]

Press Coverage (highlights)

Raising +
Dissertation: Intervention effects​ in the acquisition of Raising and Control

In my dissertation I investigate two constructions that are not fully mastered until school age: Subject-to Subject Raising verbs such as ‘seem’ (e.g., John seems (to Mary) to be nice) and Subject Control verbs such as ‘promise’ (e.g., John promised (Mary) to be nice). Despite the extensive literature on the acquisition of these constructions in English, there is no consensus as to why they are late to develop.  One prominent explanation holds that the delay is due to the presence of an intervening argument (the experiencer/benefactive Mary). Crucially, in Spanish an intervener is possible with ‘prometer’ (as with ‘promise’) but not with the functional verb ‘parecer’ (in contrast to ‘seem’). The results from this study show: (i) English-speaking children have difficulties with raising 'seem' until the age of 6. Contrastively, Spanish-speaking children perform well with raising 'parecer' by the age of 4. This behavioral difference is accounted for if we assume a more complex syntactic derivation for English, namely, the presence of a structurally intervening experiencer argument that forces a circumventing operation; (ii) Both English- and Spanish-speaking children have difficulties with 'promise'/'prometer' until at least 6-years-old, consistent with the idea that intervention is at play. However, (iii) we do not find a correlation in performance between raising 'seem' and control 'promise', which suggests these are not derived similarly. Finally, (iv) we find evidence for both grammatical and processing factors affecting children's performance on intervening constructions. This study has been supported by the National Science Foundation Doctoral Dissertation Research Grant (BCS-1451589). Different parts of this study were presented at LSA 2016 in Washington D.C. on January 2016; GALANA 7, in Urbana-Champaign, IL, on September 8, 2016, BUCLD 41, in Boston University, MA, on November 6, 2016, and LSA 2017 in Austin, TX, on January 6, 2017.


  • Mateu, Victoria & Nina Hyams. (2021). On children’s late acquisition of raising ‘seem’ and control ‘promise’: Is a unified account possible? In Adriana Belletti & Chris Collins (eds.) Smuggling, 222-254. Vol. in Oxford Studies in Comparative Syntax. Oxford: Oxford University Press. [pdf]

  • Mateu, Victoria & Nina Hyams. (2019). On the learnability of implicit arguments. In Tania Ionin & Matthew Rispoli (eds.) Three Streams of Generative Language Acquisition Research, 185-201. Vol. 63 of Language Acquisition & Language Disorders. Philadelphia, PA: John Benjamins. [pdf]

  • Mateu, Victoria. (2019). Intervention effects in the acquisition of raising: Evidence from English and Spanish. Language Acquisition. 1-34. [pdf]

  • Mateu, Victoria. (2018). What cross-linguistic acquisition differences can tell us about invisible syntax: The case of Spanish ‘parecer’. Proceedings of the 41st Boston University Conference on Language Development [BUCLD 41]. 481-494. Somerville, MA: Cascadilla Press. [pdf]

  • Mateu, Victoria. (2016). Intervention Effects in the Acquisition of Raising and Control: Evidence from English and Spanish. Los Angeles, CA: UCLA Dissertation. [link]

Word segmentation
A cross-linguistic investigation of word segmentation (with Megha Sundara)

Part I. Monolingual English infants

Infants’ ability to segment words from fluent speech is affected by their language experience. We test four hypotheses: 1. Infants can segment words in a rhythmically-similar language (e.g., stress-timed/stress-timed) but not in a rhythmically-different one (e.g., stress-timed/syllable-timed), 2. Infants can segment words that share the predominant stress pattern of their native language (trochee/trochee), but not those that do not (e.g., trochee/iamb), 3. Infants can segment in any language by using statistical cues, 4. Infant can use stress-based cues to segment words in any language as long as it has lexical stress. In order to disentangle these hypotheses we investigated the segmentation abilities of 8-month-old monolingual English infants with Spanish trochees and iambs (Spanish has lexical stress), and French iambs (French has no lexical stress) using the classic HPP procedure at the UCLA Language Lab. We found that that monolingual English-learning infants can segment Spanish trochees and iambs given an extended familiarization time (60s but not 45s). However, they fail to segment French iambs given the same familiarization time. This shows that infants can segment (i) in a rhythmically different language (Spanish) and (ii) words that have an unfamiliar stress pattern (iambs). However, they fail to segment words in a language with no lexical stress, e.g., French. This study was presented at WILD 2013, at the Basque Center on Cognition, Brain and Language (BCBL), in San Sebastian, Spain, and has been recently published in Cognition.


Part II. Monolingual Spanish and English-Spanish Bilingual infants

The focus of this study is whether monolingual Spanish and bilingual English-Spanish infants can segment disyllabic words in Spanish and/or English. Both Spanish and English have lexical stress. In contrast to English, where 90% of disyllabic words start with a stressed syllable, stress in Spanish is much more variable. Using the Head-turn Preference Procedure, we found that while monolingual Spanish 8-month-olds fail to segment Spanish CVC.CV trochees and CV.CVC iambs, bilingual 8-mo-olds exposed to both English and Spanish successfully segment Spanish CVC.CV trochees and CV.CVC iambs, as well as English iambs, even though monolingual English 8-mo-olds fail at that same task. Thus, while word-segmentation strategies are language-specific, they may be transferred between languages, even across rhythmically-different ones. We are currently investigating whether they are segmenting the full word or only the stressed syllable (or both). Part of the results from the bilingual study were presented at WILD 2015, at Stockholm University, Sweden, Bilingualism Matters 2017 at UCR, and at the International Symposium on Bilingualism 12 (ISB12), at the University of Alberta, Edmonton, Canada.


  • Mateu Victoria & Megha Sundara. (2022). Spanish input accelerates bilingual infants' segmentation of English words. Cognition, 218. 104936 [link]

  • Sundara, Megha & Victoria Mateu. (2018). Lexical stress constrains English-learning infants’ segmentation in a non-native language. Cognition 181. 105-116. [link]

Object clitics
Object clitic omission in child Spanish

This study explores the widely documented difficulty children have with object clitics in the acquisition of Romance languages. It reports on two experiments: a production task and a comprehension task. Results from the elicitation task confirm that object omission occurs at nonnegligible rates in 2- and 3-year-olds. Findings from the sentence-picture matching task show that children do not sanction a grammar with referential null objects, as suggested by previous research, and that children do not always assign a transitive interpretation to clitic constructions. Further analysis reveals that both the frequency of object omissions in production as well as the results in the clitic conditions of the receptive task are strongly negatively correlated with an independent measure of verbal working memory (nonword repetition task), consistent with the hypothesis that object clitic omission is affected by linguistic processing and short-term memory limitations

 Part of this study was presented at BUCLD 38 and has been published in its entirety in Language Acquisition: A Journal of Developmental Linguistics, you can download a copy here.


  • Hyams, Nina, Victoria Mateu, Robyn Orfitelli, Michael Putnam, Jason Rothman & Liliana Sánchez. (2015). Parameters in language acquisition and language contact. In Antonio Fabregas, Jaume Mateu & Michael Putnam (eds.) Contemporary Linguistic Parameters. 353-375. New York, NY: Bloomsbury. [pdf]

  • Mateu, Victoria. (2015). Object clitic omission in child Spanish: Evaluating representational and processing accounts. Language Acquisition 22. 240-284. [pdf]

  • Mateu, Victoria (2014). Clitic omission in Spanish-speaking children: Evaluating the roles of competence and performance. Proceedings of the 38th Boston University Conference on Language Development [BUCLD 38]. 306-318. Somerville, MA: Cascadilla Press. [pdf]

  • Mateu, Victoria. (2013). Clitic Omission in Spanish-speaking Children: Evaluating the Roles of Competence and Performance. Los Angeles, CA: UCLA Thesis. [pdf]

Indefinites + numerals
The acquisition of Spanish indefinite and numeral 'un' (with Nina Hyams)

Previous studies have argued that children draw on the meanings of known scale-mates when interpreting unknown numerals.  Under these accounts, the child first assumes a weak ‘at least’ meaning of one (one = a).  Only once they acquire the weak meaning of two (‘at least two’), they are able to strengthen the meaning of one to ‘exactly one’ by computing a contrast-based scalar implicature. In the Romance languages, however, the phonological forms for the numeral one and the singular indefinite article a are the same, i.e. un.  

We tested Spanish-speaking children aged 3-5 on their interpretation of un (a/one) and other numerals and quantifiers in a truth-value judgment task and a sentence-picture matching task. Children performed significantly better with dos 'two' and tres 'three' than with un. Unlike English-speaking children, Spanish-speaking children assign ‘un’ an ‘at-least’ reading, as they do for the quantifier ‘algunos’ (some), even after learning the ‘exact’ meaning of higher numerals, consistent with claims that ‘un’ is only an indefinite and not a numeral (a.o. Kayne, 2009). Additionally, we found that Spanish-speaking children are relatively delayed in the acquisition of the exact meaning of two and higher numerals as compared to English-speaking children. These results provide further evidence for the hypothesis that the acquisition of numerical concepts can be accelerated or delayed by the morphosyntactic use of number and number words, and that the (lack of) exact meaning for numerical concepts is at least partially bootstrapped from the language system. The results of this study were presented in GALANA 2015, at the University of Maryland, MD.



  • Mateu, Victoria & Nina Hyams. (2016). One is the loneliest number: The acquisition of Spanish indefinite ‘un’. Proceedings of the 6th Generative Approaches to Language Acquisition: North America [GALANA 6]. 73-80. Somerville, MA: Cascadilla Press. [pdf]

Clitics + Logophoricity
Antilogophoricity in clitic clusters (with Isabelle Charnavel)

In some Romance languages, including Spanish and French, there is an interesting asymmetry concerning the behavior of isolated clitics and clitic clusters with respect to coreference. In the Spanish example Anai cree que se lai recomanderán para el ascenso ‘Annai thinks that they will recommend heri to him for the promotion’, the accusative clitic la ‘her’ in the embedded clause cannot corefer with Anna when a dative clitic se ‘to him’, co-occurs in the cluster. The only previous account of this constraint (Bhatt and Šimík, 2009) attributes this to a binding restriction. Based on an online grammaticality judgment task disentangling binding and logophoricity, I found that the generalization capturing the distribution of clitics clusters in Spanish is the following: an accusative clitic cannot be clustered with a dative clitic if the accusative clitic refers to a logophoric center and is read de se. Subsequent collaborative work with Isabelle Charnavel, at Harvard University, has been able to replicate the findings in French. We derive this antilogophoricity effect from perspective conflicts, which we represent as intervention effects in the presence of a single logophoric operator in the relevant domain. This analysis furthermore provides a semantic motivation for intervention effects that have been postulated for the Person-Case Constraint (PCC), which we hypothesize also derives from perspective conflicts. Parts of this study were presented at WCCFL 32, GLOW 37, and LSRL 44. You may download the Linguistic Review paper here.


  • Charnavel, Isabelle & Victoria Mateu. (2015). The Clitic Binding Restriction revisited: Evidence for Antilogophoricity. The Linguistic Review 32(4). 671-701. [pdf]

  • Charnavel, Isabelle & Victoria Mateu. (2015). Antilogophoricity in clitic clusters. Proceedings of the 32nd West Coast Conference on Formal Linguistics [WCCFL 32]. 1-10. Somerville, MA: Cascadilla Press. [pdf]

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