# Brazilian-Portuguese-learning preschoolers use phrasal prosody to constrain their interpretation of ellipsis

Letícia S Kolberg, A. de Carvalho, A. Christophe

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Letícia S Kolberg, A. de Carvalho, A. Christophe. Brazilian-Portuguese-learning preschoolers use phrasal prosody to constrain their interpretation of ellipsis. Language Learning and Development, In press, 10.1080/15475441.2025.2593822. hal-05405406

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Brazilian-Portuguese-learning preschoolers use phrasal prosody to
constrain their interpretation of ellipsis.

Letícia S. Kolbergª*, A. de Carvalhoª and A. Christopheᵇ

ªLaboratoire de Psychologie du Développement et de l'Éducation de l'Enfant
(LaPsyDÉ), Department of Psychology, Université Paris Cité, CNRS, F-75005, Paris,
France;

ᵇLaboratoire de Sciences Cognitives et Psycholinguistique, DEC-ENS / EHESS / CNRS,
Ecole normale supérieure, PSL University, Paris, France

<footnote>*Corresponding author: correspondance concerning this article should be addressed to
Letícia S. Kolberg, email: leticia.kolberg@gmail.com. Address: Laboratoire de
Psychologie du Développement et de l'Éducation de l'Enfant (LaPsyDÉ), La Sorbonne,
46 rue Saint Jacques, 75005 Paris, France</footnote>
**Brazilian-Portuguese-learning preschoolers use phrasal prosody to
constrain their interpretation of ellipsis.**

**Abstract.** Phrasal prosody is believed to be crucial for syntactic and lexical acquisition, since prosodic boundaries in speech tend to coincide with lexical and syntactic boundaries. However, research on children's ability to exploit prosodic information for parsing reports mixed results, with some providing positive evidence in French while many studies in other languages fail to observe this ability in children up to 6-years-old. To further investigate whether the discrepancies between these studies stem from cross-linguistic or methodological differences, we adapted a recent preferential-looking experiment conducted with French children to a different language: Brazilian Portuguese. Brazilian Portuguese-learning 3-to-4-year-olds were presented with either ellipsis (e.g., [The tiger is poking!] [The duck too!]) or transitive sentences (e.g., [The tiger] [is poking the duck too!]), while watching two videos side-by-side, one depicting the transitive interpretation of the sentences, and another depicting the ellipsis interpretation. Results showed that 3-to-4-year-olds successfully exploited prosodic information to distinguish ellipsis from transitive sentences and therefore constrain their parsing. Children in the ellipsis condition looked more at the video depicting the ellipsis interpretation than children in the transitive condition. This result provides cross-linguistic evidence for the role of prosody in constraining parsing in young children.

**Introduction**

From the beginning of language acquisition, young learners are confronted with the task
of segmenting the speech signal into meaningful units, to learn words and uncover the
syntactic structure of sentences in their native language(s). To do so, they need to look
for cues in their speech input that could flag the boundaries between words and syntactic
constituents, as well as the grammatical relations between words in sentences. Numerous
studies propose that the suprasegmental cues of speech (e.g., pitch, duration, energy, etc.)
are one of the primary cues that children use for this purpose, as they indicate, among
other things, prosodic phrase boundaries (e.g., Babineau et al., 2024; Christophe et al.,
2016, 2008; de Carvalho et al., 2019, 2018; Hawthorne & Gerken, 2014; Hawthorne, Mazuka, & Gerken, 2015; Massicotte-Laforge & Shi, 2015, 2020; Morgan & Demuth, 1996).

Previous studies show that children know a great deal about their native language's prosodic structure, and use this knowledge for many different aspects of sentence parsing, such as sentence disambiguation (e.g., Dautriche et al., 2014; de Carvalho et al., 2016a, 2016b, 2017; Kolberg et al., 2021; Snedeker & Yuan, 2008), word and sentence segmentation (e.g., Bailey & Plunkett, 1998; Gervain & Werker, 2013; Graf Estes & Bowen, 2013; Hirsh-Pasek et al., 1987; Johnson, 2008; Johnson & Seidl, 2008; Jusczyk et al., 1992; Mandel, Jusczyk, & Nelson, 1994; Ramachers, Brouwer, & Fikkert, 2017; Shukla, White & Aslin, 2011; Soderstrom et al., 2003) and grammatical categorization of novel words (e.g., de Carvalho et al., 2019; Hawthorne & Gerken, 2014; Massicotte-Laforge & Shi, 2015). The *prosodic bootstrapping hypothesis* (e.g., Christophe et al., 2008, 2016; Gutman et al., 2015; Höhle et al., 2001; Morgan & Demuth, 1996) posits that, since prosodic and syntactic phrasing tend to align (e.g. Nespor & Vogel, 1986) in such a way that whenever a prosodic boundary occurs, there is often also a syntactic boundary, then phrasal prosody becomes crucial to assist language learners in extracting word forms from the speech stream and delineating syntactic constituents within sentences.

Children have indeed been shown to pay attention to prosodic cues in speech even before they are born (e.g., Abboub, Nazzi & Gervain, 2016; Mehler et al., 1988). Mehler et al. (1988), for instance, has shown that newborns can discriminate between languages through their different prosodic properties. Other studies suggest that, at around 6 to 10 months, infants can rely on prosodic cues to constrain their segmentation of the speech stream (Gout, Christophe, & Morgan, 2004; Johnson, 2008; Johnson & Jusczyk, 2001;
Jusczyk, Cutler, & Redanz, 1993; Morgan & Saffran, 1995; Shukla, et al., 2011), and are sensitive to the coalition of cues that signal prosodic boundaries in their native language (Hirsh-Pasek et al., 1987; Jusczyk et al., 1992; Soderstrom et al., 2003; van Ommen et al., 2020; Wellmann et al., 2012). Jusczyk et al. (1992) and Hirsh-Pasek et al. (1987), for instance, showed that by 7 months of age, infants pay more attention to recorded stories in which pauses are inserted correctly at the level of prosodic boundaries, as opposed to within prosodic phrases. Infants have also been shown to understand, from 6 months onwards, that words cannot span prosodic boundaries, i.e., that a word cannot start in a prosodic phrase but end in a different phrase (e.g., Gout et al., 2004; Shukla et al., 2011; Soderstrom et al., 2003).

Although the above-mentioned studies show that children are aware of prosodic information in the speech signal and can use it to segment words and sentences, they do not tell us, on their own, whether children can use prosodic information for syntactic parsing and to guide the acquisition of syntax. In fact, studies on this matter have reported mixed results. While some studies provide positive evidence for this ability in young children (e.g., in French: de Carvalho et al., 2016a, 2017, 2019; Massicotte-Laforge & Shi, 2015, 2020; and in English: de Carvalho et al., 2016b; Snedeker & Yuan, 2008), other studies failed to observe it in children up to 6 years old (e.g., in English: Snedeker & Trueswell, 2001; and in Korean: Choi & Mazuka, 2003). de Carvalho et al. (2016a) found that French-learning 20-month-olds can exploit prosodic boundary information to correctly interpret globally ambiguous sentences such as “Tu vois le bébé /suːbi/”, where the homophone /suːbi/ could be interpreted as the verb “smile” or the noun “mouse” depending on the prosodic phrasing of the sentences, which reflects different syntactic structures. When there is a prosodic phrase boundary between “le bébé” and the homophone, the latter has a verb interpretation (“[Tu vois]? [Le bébé] [/suːbi/]!” – “[Do
you see]? [The baby] [smiles]!”, with brackets representing prosodic phrasing); but when all the words in the sentence are pronounced within a single prosodic unit, it has a noun interpretation (“[Tu vois le bébé /suki/]?” – “[Do you see the baby mouse]?”). When presented with two images depicting the two possible interpretations (e.g., a baby smiling (verb interpretation) and a little mouse (noun interpretation)) side-by-side on a screen, children who listened to the sentences with noun prosody looked longer towards the noun image, while children who listened to the sentences with verb prosody looked longer towards the verb image.

The ability to use prosody to constrain parsing of noun-verb homophones was also attested in older French- and English-speaking children in oral completion tasks. In a second study presented in de Carvalho et al. 2016a, French-speaking 4-to-5-year-olds listened to sentences such as [le bébé /suki/][a bien mangé] (“the baby mouse has eaten well”) or [le bébé] [/suki/ à sa maman] (“the baby smiles to his mother”). Crucially, all words following the homophone /suki/ were acoustically masked, such that prosodic cues were the only disambiguating information children could exploit to guide their interpretations. French children heard these three-word sentence onsets either in the noun prosody condition (e.g., [le bébé souris]...) or in the verb prosody condition (e.g., [le bébé] [sourit...]) and were then asked to orally complete the sentences using their own words. French 4-to-5-year-olds successfully exploited prosody to interpret the ambiguous word as a noun in the noun prosody condition, and as a verb in the verb prosody condition.

This result was replicated with English-speaking 4-to-5-year-olds in de Carvalho et al. (2016b), using the same methodology and the same type of ambiguity as the French study, but with English sentences.

Examples of studies that did not find evidence of children's ability to use prosody to constrain parsing come from Choi & Mazuka (2003) and Snedeker & Trueswell (2001).
In Choi & Mazuka's study, 3-to-4 and 5-to-6-year-old Korean-speaking children were presented with sentences in which the first noun could either be considered as the subject of the sentence, as in [kirin] [kwaja məgəyo] (giraffe cookie eat, meaning "the giraffe eats cookies") or as a modifier of the object in a null-subject sentence, as in [kirin kwaja məgəyo] (giraffe cookie eat, meaning "(someone) eats giraffe-shaped cookies"). Children listened to one of these two types of sentences, while seeing two images side-by-side: one image of a child eating giraffe-shaped cookies, and another image of a giraffe eating cookies. In a pointing task, children from both age groups did not appear to use prosodic cues to correctly disambiguate the two sentence types.

In Snedeker and Trueswell's (2001) study, English-speaking 5-year-olds were exposed to ambiguous sentences such as "*Tap the frog with the flower!*" and had to perform the action described in the sentence with a set of toys (i.e., a frog, a flower, and a frog carrying a small flower). Although the prosodic phrasing correctly cued the right interpretation of the sentences in the ambiguous contexts<fnref n="1" /> (e.g., [tap the frog] [with the flower] for the instrument interpretation (tap the frog using the flower) vs. [tap] [the frog with the flower] for the modifier interpretation (tap the frog who is carrying a flower)), children's interpretations were at chance, whereas they nearly always performed the correct actions when listening to the unambiguous versions of the same type of sentences.

The studies reviewed above illustrate the mixed results found in the literature and raise the question of why children can use prosody to constrain parsing in some tasks/languages but not in others. One possible explanation is that these discrepancies arise from differences in how languages use prosodic information for different linguistic

<footnote n="1">¹ A similar experiment was conducted with adults, who succeeded in disambiguating the test sentences and performing the correct actions (Snedeker & Trueswell, 2003).</footnote>
functions. While previous studies in French have consistently yielded positive results, findings in other languages, such as English, are more mixed. One key difference between these languages is that French and English differ notably in how they use prosody to convey meaning and mark different types of linguistic functions such as stress, focus, and topic marking. For instance, while English has lexical stress and relies heavily on prosodic cues to highlight topic and focus, French lacks word-level stress, and prosodic marking of topic and focus tends to be optional and infrequent in adult speech (e.g., Esteve-Gibert et al., 2022; Féry, 2001)<fnref n="2" />. Although these different prosodic functions are clearly identifiable for mature speakers, children learning languages in which prosody serves multiple purposes may require more time and exposure to learn how to interpret these cues reliably. In this sense, prosodic cues in languages like English may initially be ambiguous for young children, who must first learn how to distinguish prosodic cues that mark phrase boundaries from those that signal other linguistic functions. This could explain the contrast between French studies —demonstrating young children's ability to use prosodic boundaries for syntactic parsing—and studies in other languages, which report more variable results.

Alternatively, discrepancies in the literature may stem from methodological
differences between studies. Because both successful and unsuccessful findings have
been reported using a range of methods (e.g., eye-tracking, act-out, or pointing tasks), it
remains unclear whether any particular method is inherently better suited to assessing
children's use of prosody for parsing. Rather, some studies suggest that performance

<footnote n="2">² Languages with lexical stress are more likely to use prosody to mark topic and focus, as lexical stress provides a prosodic foundation for manipulating local prominence (e.g., Selkirk, 1984; Ladd, 2008). However, some languages without lexical stress also mark topic and/or focus prosodically, as seen in Korean, for example (e.g., Lee, Shin, & Garcia, 2019).</footnote>
differences may arise from specific design decisions that introduce bias in children's performance. Snedeker & Yuan's (2008) study clearly illustrates this possibility. Using the same sentence types and act-out methodology as Snedeker & Trueswell (2001), they made several methodological adjustments to reduce potential biases. Rather than a randomized within-subjects design, they used a blocked design in which children first heard all test sentences from one prosody condition followed by those from the other condition, to avoid perseveration effects. They also revised some lexical items to reduce interpretation biases and slightly altered sentence structures to improve prosodic naturalness (e.g., "Can you tap the frog with the flower?"). In this revised task, 4- to 6-year-olds succeeded in using prosodic cues to constrain interpretation, but only in the first testing block. Although it remains unclear which specific changes led to this improvement, the findings suggest that the earlier null results may have stemmed more from methodological artifacts than from children's inability to use prosody for parsing.

The English results from de Carvalho et al. (2016b), described above, also indicate that when the methodology of successful French studies is applied, English-speaking children perform similarly to their French peers of the same age and reliably use prosody to constrain parsing.

Finally, another factor that may affect children's ability to use prosody to constrain parsing is the complexity and/or frequency of sentences used in each study. In Snedeker & Trueswell (2001), children were exposed to sentences containing a prepositional phrase (e.g., "with the feather") that could be attached to either the object or the verb phrase. These sentences might be more complex for children to parse, compared to the sentences used in previous French studies, which mainly contained a simple (adjective)subject-verb-object format, and children simply had to decide whether the words they heard were grouped together into a single noun phrase or in a noun phrase
plus a verb phrase. Additionally, while the prosodic phrasing of sentences in de Carvalho et al. (2016a,b) is inherently disambiguating (the default prosodic phrasing is different for the two versions of the ambiguous sentence), the disambiguating prosodic phrasing in Snedeker & Trueswell's sentences is optional (i.e., when pronounced with 'neutral', default phrasing, the sentences remain ambiguous). Sentences such as "feel the frog with the feather" might be more often disambiguated through context, or through syntax (e.g., "feel the frog that is carrying a feather") than via prosodic cues. The same observation could explain the results from Choi & Mazuka's study described above. It is thus possible that children have more difficulty using prosody to disambiguate sentences that are typically disambiguated by other means and/or that are more complex or less frequent in their input. This may be due to reduced exposure to these types of sentences, the additional processing cost of complex structures, or limited experience with contexts in which prosody serves as the primary cue for disambiguation.

To further investigate the role of sentence complexity/frequency in children's performance, Kolberg et al. (2021) investigated French children's ability to use prosody to parse a type of structure which is more complex and less frequent in French than the ones previously studied. It compared ellipsis sentences such as [*Le tigre tape!*] [*Le canard aussi!*] ([The tiger is hitting!] [The duck too!]), which are interpreted as indicating that a tiger and a duck are hitting a third character, with transitive sentences such as [*Le tigre* [*tape le canard aussi!*] ([The tiger] [is hitting the duck too!]), which are interpreted as meaning that the tiger is hitting the duck as well as some other character. These sentences are linearly ambiguous, meaning that they present the exact same words in the same order, but their different prosodic phrasings clearly indicate their different syntactic structures. Although ellipses are very common among languages (Barss, 2003), and some studies show that children understand and produce ellipsis sentences from around 3 years of age
(e.g., Foley et al., 2003; Lindenbergh, Van Hout & Hollebrandse, 2015; Postman et al., 1997), children could have more trouble interpreting these types of sentences solely through prosodic information, since they require the recovery of an absent element. Moreover, such sentences seem less common in French children's input compared to the type of sentences tested in previous studies. In Kolberg et al.'s study, children listened to either ellipsis or transitive sentences while watching two videos side-by-side: one depicting the transitive interpretation (e.g., a duck and a tiger hitting a bunny), and another depicting the ellipsis interpretation (e.g., the tiger hitting the duck and the bunny). The results showed that 3-to-4-year-olds correctly interpreted the ellipsis sentences differently from the simple transitive sentences. Children who listened to sentences with ellipsis prosody looked significantly longer towards the video illustrating the ellipsis interpretation than children who listened to sentences with transitive prosody. However, a group of 28-month-olds tested in the same task presented only a marginally significant trend in the expected direction. These results suggest that French-learning children can use prosody to constrain parsing of sentences that are more complex and less frequent than the ones previously studied, although they seem to take more developmental time to be able to do so. While previous studies in French showed that even 20-month-olds can use prosody to constrain parsing of globally ambiguous sentences containing noun/verb homophones, in Kolberg et al., French 28-month-olds were not as successful with ellipsis sentences, suggesting that the complexity of the syntactic structure tested can impact children's ability to use prosody to constrain parsing.

These results highlight the importance of exploring how children's ability to use prosody to constrain parsing may vary according to the different languages, sentence structures and methodologies used in different studies. Snedeker and Yuan's (2008) study, for instance, suggests that children's failure in Snedeker and Trueswell (2001) was likely
due to methodological issues. The study done by de Carvalho et al. (2016b) indicates that when presented with the same type of ambiguity and methodology from previous successful French studies, English children perform as well as their French peers. However, since previous studies on languages other than French did not measure children's online performance, it remains unclear when prosodic information was integrated during the parsing process, and whether children learning languages that use prosodic information for many linguistic functions (e.g. lexical stress, prosodic prominence and phrasal boundaries, like English and Brazilian Portuguese) are as quick as their French peers in exploiting prosodic information to constrain parsing in real time.

To better understand how children use prosody to constrain syntactic parsing, further research is needed to clarify the variability in previous findings — particularly the extent to which cross-linguistic and/or methodological factors account for it — and to examine how children across languages integrate prosodic cues in real time. To contribute to this goal, the present study adapts the methodology of Kolberg et al. to Brazilian Portuguese, a language not previously tested in this type of task. Like English, Brazilian Portuguese features lexical stress and frequently uses prosodic information for topic and focus marking. Since the structures used in Kolberg et al.'s (2021) study in French are equally productive in this language, this paradigm will allow us to see how children learning a language in which prosodic cues serve more linguistic functions than in French can use prosodic information to constrain parsing of the same type of structure, in a similar task.

We presented 3-to-4-year-olds with ellipsis sentences such as [O tigre tá cutucando!] [O pato também!] ([The tiger is poking!] [The duck too!]) or with simple transitive sentences such as [O tigre] [tá cutucando o pato também!] ([The tiger] [is poking the duck too!]). The ellipsis sentence is produced with a major prosodic boundary
(IP – Intonational Phrase boundary) after the verb, and should be interpreted as two main sentences, with both the tiger and the duck being the agents of the action “hit” in each phrase. The verb is elided (i.e., deleted) in the second phrase via a syntactic process called stripping (Ross, 1969). The transitive sentence is produced with a minor prosodic boundary (PP - Phonological Phrase boundary) before the verb (i.e., between the subject noun phrase and the verb phrase) and all the words are part of the same main sentence, in which the tiger is the agent of the action and the duck is the patient.

Following the same experimental design from Kolberg et al.'s (2021) study, Brazilian Portuguese-learning children listened to either ellipsis or transitive sentences while watching two videos side-by-side: one depicting the transitive (one-agent) interpretation (e.g., a tiger poking a duck and a bunny), and another depicting the ellipsis (two-agent) interpretation (e.g., a tiger and a duck poking a bunny; see Figure 2). We measured children's looks towards the videos while they listened to each type of sentence during test, as well as their pointing responses to the request "show me which video the lady was talking about" (*me mostra de que vídeo a moça tava falando*), which they heard at the end of each trial. These different measures were also used in Kolberg et al., (2021) and allowed us to assess both children's real-time, implicit interpretations (via looking data) and their off-line, explicit interpretations (via pointing responses). Including both measures has the added benefit of maintaining children's engagement, as pointing tasks may help sustain their interest.

This study aims to add a new language to the literature, one that has not been studied before for this type of task, and that, like English, uses prosody for different linguistic functions other than prosodic boundaries. As noted by Kidd & Garcia (2022), much of the existing evidence in child language acquisition research comes from a small number of languages, such as English and French, which limits the generalizability of
current findings. By investigating Brazilian Portuguese, we sought to contribute to a more inclusive and representative understanding of children's language acquisition across the world's linguistic diversity.

If Brazilian 3-to-4-year-olds succeed in using prosody to constrain their interpretation of ellipsis vs. transitive sentences, this will show that children can use prosodic cues to disambiguate complex sentences even in languages in which prosodic information might be more ambiguous than in French. Furthermore, by investigating Brazilian children's real-time interpretation, we also address the question of whether children learning languages in which prosodic information cues multiple linguistic functions can exploit prosodic cues as rapidly as their French-speaking peers during sentence processing.

## Materials and methods

This experiment was approved by the Ethics Committee of the State University of Campinas before its conducting (approval number: 84251818.5.0000.8142). The method, data analysis and criteria for exclusion of participants were pre-registered on the OSF (Open Science Framework) database before running the study. Materials, collected data, data analysis and additional exploratory analyses are freely available to readers at https://osf.io/98cmu/?view_only=9383d5ea4f2a40c0860171ab7f41c222.

## Participants

For the Preferential Looking task, fifty children ranging from 36 to 50 months old<fnref n="3" /> (twenty-five children in the transitive condition ($M_{age} = 41.3$ months, range 36 to 49.8,

<footnote n="3">³ This age was chosen to match the age range in which we found successful results with ellipsis sentences in French (Kolberg et al., 2021).</footnote>
12 girls), and twenty-five in the ellipsis condition ($M_{age} = 41.8$ months, range 34.6 to 50.2, 16 girls)) were included in the final analysis. Children were recruited from two daycare facilities at the city center of Campinas, Brazil. Since both facilities are non-profit institutions, children there come mostly from low to middle-low SES families. All children were monolingual Brazilian Portuguese speakers. Parents signed an informed consent form handed by the children's teachers along with a short letter of invitation explaining the purpose of our study.

An additional eighteen children were tested but not included in the analysis because of insufficient eye-tracking data (13 children)<fnref n="4" />; fussiness (4 children); and refusal to participate (2 children). Those not included in the analysis because of missing eye-tracking data did not have their pointing data discarded, as this was not judged to be caused by children's lack of attention to the videos.

For the pointing task, forty-three children were included in the final analysis. From this group, twenty-one children were in the transitive condition ($M_{age} = 42.2$ months, range 36 to 53.1, 9 girls), and twenty-two were in the stripping condition ($M_{age} = 42.3$ months, range 34.6 to 50.2, 13 girls). Twenty-five children were excluded from the pointing analysis, due to refusal to point (9 children); side bias (where children consistently pointed to the same side across the four test trials and the training trial) (13 children); and fussiness (3 children - the same excluded from the looking analysis minus one, who also refused to point).

<footnote n="4">⁴ All trials with less than 25% of eye data (i.e., in which children looked away and/or in which the eye-tracker could not track the eye for more than 75% of the time of the trial) were excluded from the statistics, and children with more than two excluded trials had all their looking data discarded.</footnote>
## Materials

The experimental design was identical to the one used in Kolberg et al. (2021), except for the language. We presented children with four pairs of test videos featuring animal puppets. We used the same videos from Kolberg et al. (2021), except for one of the test actions: while Kolberg et al. (2021) used the actions “eat”, “push”, “carry” and “hit”, in our experiment we replaced “hit” by “poke”, since the equivalent of the verb “hit” in Brazilian Portuguese requires a preposition, and the ellipsis sentence would have an extra word compared to the transitive sentence. Each test trial started with an introduction video, which intended to familiarize children with the verbs used in the test sentences and provide pragmatic context for the transitive sentences (one does not say, e.g., “the tiger is poking the duck too” without some preceding context where the tiger was poking someone else). In these videos, the first character mentioned in the test sentence performed an action on a third character, accompanied by a sentence such as “Olha! É o tigre! E o coelho! Oh, ele tá cutucando ele!” (“Look! It's the tiger! And the bunny! Oh, he is poking him!”) for the “poke” action.

Regarding the test videos, for each pair, one video corresponded to the interpretation of the simple transitive test sentence (i.e., the one-agent video – a tiger poking a duck and a bunny with a stick, for the “poke” action) and the other corresponded to the interpretation of the ellipsis sentence (i.e., the two-agent video – a tiger and a duck poking a bunny with a stick at the same time, for the “poke” action). For the actions “eat” (*comer*), “push” (*empurrar*) and “poke” (*cutucar*), both test videos contained three animal puppets, but the transitive videos had one agent and two patients, while the ellipsis videos had two agents and one patient. For the “carry” (*carregar*) action, the transitive video contained two animals (i.e., a duck and a dinosaur) and a gift box: the duck was the agent, and the dinosaur and the gift box were the patients (i.e., the things being carried). The
ellipsis video contained the same animals but two gift boxes, which were the patients of the individual “carry” actions<fnref n="5" />. The quantity and quality of movements, as well as characters' position on the screen was controlled for each video pair, so that both videos were as similar as possible in terms of complexity.

The sentences used in the experiment were adapted from the French sentences from Kolberg et al. (2021) maintaining the same nouns and verbs, except for the verb “hit” (*taper*), which was replaced with “poke” (*cutucar*) in Brazilian Portuguese. The sentences were recorded by a female native Brazilian Portuguese speaker, using a professional recorder and a condenser microphone. The speaker was instructed to say the sentences as if they were speaking to a child. Before conducting the experiment, twenty-nine Brazilian Portuguese-speaking adults were asked to interpret the recorded sentences via an online form made with Google Forms. Participants were asked to listen to each test sentence through headphones and to indicate their interpretation of the sentences on a 5-point scale, 1 being the simple transitive interpretation (e.g., “the tiger is poking the duck”); 5 being the ellipsis interpretation (e.g., “the tiger and the duck are poking”); and 3 being completely ambiguous. The sentences were interpreted correctly 94% of the time<fnref n="6" /> (i.e., the ellipsis sentences were interpreted as coordinated sentences with two equivalent actions, and the transitive sentences were interpreted as if the first noun indicated the agent, and the second noun indicated the patient of the action).

## Acoustic analyses

To assess the prosodic differences between our test sentences in each condition (ellipsis

<footnote n="5">⁵ See Table A.1 in the Appendix for a detailed description of all video stimuli and Table A.2 for the detailed video design.</footnote>

<footnote n="6">⁶ 98% of correct judgements for ellipsis sentences, and 97% for transitive sentences.</footnote>
vs. simple transitive prosody), we followed the same analysis done in Kolberg et al., (2021) conducting acoustic measurements around the positions of the prosodic phrase boundaries in the sentences recorded for the experiment. We selected three acoustic parameters which usually cue phrase boundaries in natural languages (e.g., Nespor & Vogel, 1986): presence and length of pauses; duration of the rhyme in the word preceding the prosodic boundary (e.g., “tigre” and “cutucando”); and pitch (F0) contour around prosodic boundaries. For the boundary between the first noun and the verb, we calculated the difference between the maximum pitch of the vowel preceding the boundary (e.g., [i] in ['tʃɪgrɪ] (“tiger”)) and the maximum pitch of the vowel following it (e.g., [a] in ['ta kutu'kɛdʊ] (“is poking”)). For the boundary between the verb and the second noun, we focused on the verb's stressed vowel, which in this case is the one immediately preceding the last vowel. This choice was made because the last vowel demonstrated coarticulation effects with the determiner of the second noun in transitive sentences (e.g., ['ta kutu'kɛdɒpatɔ]). Similarly, we opted for the first vowel of the actual noun in this comparison (e.g., [a] in ['patɔ]) instead of the vowel of the determiner for the same reason.

We found significant phrase-final lengthening effects. The rhyme of the first noun was significantly longer in the transitive sentences (M = 567 ms, SD = 60) than in the stripping sentences (M = 282 ms, SD = 24; t(14) = -12.49; *p* < 0.001), whereas the rhyme of the verb was significantly longer in stripping sentences (M = 454 ms, SD = 45) than in transitive sentences (M = 256 ms, SD = 17; t(14) = 11.83; *p* < 0.001). This effect was accompanied by systematic pauses between the verb and the second noun in the stripping sentences (M = 451 ms, SD = 63).

We also found significant differences in pitch contour around prosodic boundaries (max. F0 of the vowel following the boundary minus max. F0 of the vowel preceding the
boundary). For the boundary between the first noun and the verb, the transitive sentences presented an overall falling pitch contour (M = -118Hz, SD = 104) and bigger pitch discontinuity than the stripping sentences (M = 31Hz, SD = 23; t(14) = 3.96; *p* = 0.001). For the boundary between the verb and the second noun, the stripping sentences presented an overall falling pitch contour (M = -274Hz, SD = 62) and bigger pitch discontinuity than the transitive sentences (M = 90Hz, SD = 40; t(14) = -11.17; *p* < 0.001). The average duration values can be found in Table 1, and the average values of F0 can be found in Table 2.

[insert Figure 1 about here]

[insert Tables 1 and 2 about here]

These analyses show significant duration and pitch differences between transitive and stripping sentences around the intonational phrase boundary of stripping sentences (i.e., pause between the verb and the second noun; longer duration of the rhyme of the verb; and larger difference in F0 between the stressed vowel of the verb and the first vowel of the last noun), and around the phonological phrase boundaries of transitive sentences (i.e., longer duration of the rhyme of the first noun; and larger difference in F0 between the last vowel of the first noun and the first vowel of the verb).

## Procedure

Caregivers were contacted through teachers from the two selected daycare facilities in the city of Campinas, Brazil, and were asked to authorize children's participation by signing a consent form. The experimenter then went to the daycares and invited each authorized child to come to the experiment room (an empty classroom) individually to watch the test
videos. Once in the room, children were instructed to sit in front of a TV monitor, and a
pair of headphones were put on them with the help of the experimenter. Most children
accepted putting the headphones on quite easily, as they were told they were needed for
listening to the videos. They were also told they would sometimes see two videos at the
same time, but the narrator (“the lady who talks”) would talk about only one of them, and
they would be asked to point at the video she was talking about. The experimenter then
adjusted the eye-tracker position while the child watched a cartoon video. Afterwards, a
five-point calibration of the eye-tracker began, followed by the experiment. During the
experiment, the experimenter sat in a chair to the right of the child, facing the child (and
not the monitor) and looking at her own laptop screen, which children could not see, to
not influence children’s looks during the test.

The videos were presented through a commercial video player on a 21.5-inch
monitor, and the auditory stimuli was played through headphones. To avoid possible
order biases in children's responses (e.g., children could get bored during the last trials
and perform better with the first test items, or take some time to understand the task and
perform better with the last test items), we created four complete videos per condition,
alternating the order of appearance of test trials in each video so that all four test trials
appeared first in one video, second in another one, and so on<fnref n="7" />. The left-right disposition
of the videos was also randomized so children did not see more than two consecutive
target videos on the same side. Children were assigned a particular version of the video
by order of testing: the first and second child watched the first and second versions of the
ellipsis videos; the third and fourth watched the first and second versions of the simple
transitive videos; the fifth and sixth watched the third and fourth versions of the ellipsis

<footnote n="7">⁷ For a detailed description of the randomization of test videos, see the OSF repository.</footnote>
videos, and so on. The pointing responses were written down by the experimenter (and
later checked through the viewing of the children's videos without sound) and the eye
data were collected through a Gazepoint eye-tracker<fnref n="8" />.

The experiment started with an introduction of each of the puppet characters: a
bunny, a duck, a tiger, a dinosaur, and a monkey. Each puppet was presented in a five-
second video in which the character appeared waving and dancing on the screen and was
labeled once (e.g., “Olha! É o coelho!” (“Look! It's the rabbit!”)). Afterwards,
participants saw a training trial, which had the same structure as the test trials (see Figure
2) and involved the verb “pular” (“to jump”): two videos appeared side-by-side, one
displaying a rabbit jumping and the other displaying a rabbit and a monkey playing
together, accompanied by the sentence “o coelho tá pulando!” (“the rabbit is jumping!”).
This training trial familiarized children with the procedure and showed them that the
soundtrack matched only one of the two videos on the screen.

The test phase (Figure 2) started with a video introducing the characters and the
action for this trial, and was followed by a preview phase, where each action appeared
individually on the screen for nine seconds, and afterwards by a contrast phase, where
both actions appeared at the same time, also for nine seconds, with neutral attention-
getters such as “Olha! Tá vendo isso?” (“Look! Do you see that?”). At the end of the
contrast phase, the screen turned gray, and the test sentence was played for the first time
in the future tense (e.g., “Olha! O tigre vai cutucar! o pato também!” – “Look! The tiger
will poke(!) the duck too!”). Then the test videos reappeared side-by-side on the screen
for twelve seconds, while the test sentence was played two more times, but in the present
tense (e.g., “O tigre tá cutucando! o pato também!” – “The tiger is poking(!) the duck

<footnote n="8">⁸ https://www.gazept.com/</footnote>
too!). At the end of each test trial, the experimenter would pause the videos manually and ask children to point at the video "the lady was talking about" (*de qual vídeo a moça tava falando?*). Pointing responses were always congratulated, regardless of being correct or not.

Children saw a total of one training trial and four test trials (involving the actions "eat", "push", "carry" and "poke"). At the end of the experiment, the experimenter thanked the child and escorted her back to her classroom.

[Insert Figure 2 about here]

## Data analysis

The eye-tracker software generated a video and a table describing the x and y axis position of the child's eye gaze every 16.4 ms on average for each child. The experimenter determined the start of each test trial by watching the videos and labeled the entire trials in the table generated by the eye-tracker, from 0 ms to 12000ms. Once each trial was labeled, the tables went through an R script that selected only the relevant data (excluding non-labeled times) and determined the child's left-right eye position through the x and y axis values. After that, the looks to the ellipsis vs. transitive videos were determined. The data for all children were then organized in a single file for analysis.

For the looking data, we performed a cluster-based permutation analysis (Maris & Oostenveld, 2007) and a t-test for overall looking times (averaged over the entire duration of each test trial). Both analyses used the proportion of looks towards the two-agent action (i.e., ellipsis video) as the dependent variable. Since the eye-tracker did not give precisely one data point every 16.4 ms, we first averaged the data in 170 ms time bins (an average of 10 time points collected by the eye-tracker). We used the software R (R core team, 2017) and the package eyetrackingR (Dink & Ferguson, 2016) for the
analyses. For the cluster-based permutation, the analysis searched for time-window(s)
where a significant effect of condition was observed, indicating that children looked more
at the two-agent action while listening to ellipsis sentences than while listening to
transitive sentences. Since children listened to the test sentence once before the beginning
of the test trial, they could show a preference for one of the videos from the beginning of
the trial; therefore, the analysis searched for time windows during the entire test trial (0
to 12000 ms). Adjacent time points with a t-value greater than a predefined threshold (t
= 1.5, for the comparison between groups) were grouped together into a cluster, the size
of the cluster being computed as the sum of the t-values of the time-points in the cluster.
The probability of observing a cluster of the same size by chance was estimated by
running the same analysis 1000 times on simulated data, in which groups were randomly
assigned to participants.

For the pointing responses, we ran a generalized linear mixed-effects regression
with the proportion of pointing towards the two-agent video as the dependent variable
(coded as 0/1 in each trial), condition (sum coded) as a fixed effect, participants as a
random intercept and a random slope for condition by item.

Experimental hypothesis

If children can use prosodic information in ellipsis sentences to deduce their syntactic
structure, and therefore constrain their interpretation, then they should point more often
and look longer at the two-agent action when presented with ellipsis sentences than when
presented with transitive sentences. If, however, children cannot use the prosodic
boundary information from our ellipsis sentences to constrain their interpretation, then
they might interpret them as simple transitive sentences (since they present two nouns)
and look/point less often at the two-agent action, mirroring the performance of children
exposed to the transitive sentences. Another possibility is that children do not show
preference for any of the videos, looking/pointing at the one- and two-agent videos for
the same amount of time in both conditions during the entire test trial.

**Results**

***Eye-tracking data***

Figure 3 shows the time course of proportion of looks to the two-agent action during the test trials, for participants in the ellipsis condition (red line) and in the transitive condition (blue line).

[Insert figure 3 about here]

The cluster-based analysis found two significant time clusters, where children in
the ellipsis condition looked more towards the two-agent action than children in the
simple transitive condition: one at the end of the first appearance of the test sentence
during the trials (from 5270 ms to 7310 ms, *p* = .050), and another after the end of the
second repetition of the test sentence until the end of the trial (from 10540 ms to 12000
ms, *p* = .030).

Figure 4 shows the average proportion of looking times to the two-agent action averaged over the entire trial duration across all four items in the experiment, for the ellipsis condition (red box) and transitive condition (blue box).

[Insert figure 4 about here]

A t-test on overall looking times showed a significant difference between the
Ellipsis (M = .59, SD = .11) and Transitive condition (M = .50, SD = .11, t(48) = 2.95; *p*
= .004; Cohen's d = .83). Children in the ellipsis condition looked overall significantly longer to the two-agent action than children in the ellipsis condition.

## Pointing data

Figure 5 shows the average proportion of pointing towards the two-agent action for the ellipsis condition (red box) and transitive condition (blue box).

[Insert figure 5 about here]

The pointing analysis shows no significant difference in pointing between conditions (β = -.51, SE = .46, z = -1.12, p = .26). The results, however, follow the expected direction, with children in the ellipsis condition pointing more at the two-agent action (M = .65, SD = .48) than children in the transitive condition (M = .53, SD = .50).

## Discussion

In the present study, we investigated Brazilian Portuguese-learning 3-to-4-year-olds' ability to interpret ellipsis sentences such as "*[O tigre tá cutucando]*! [O pato também]!" differently from simple transitive sentences such as "*[O tigre] [tá cutucando o pato também]*!" by relying on their different prosodic structures, which reflect their different syntactic structures. We presented children with either transitive or ellipsis sentences while they watched two videos side-by-side: a two-agent video, corresponding to the interpretation of ellipsis sentences, and a one-agent video, corresponding to the interpretation of transitive sentences. The results showed that children who heard the sentences with ellipsis prosody looked significantly longer to the two-agent videos than children who heard the sentences with transitive prosody, showing that they were able to use prosodic information to constrain their interpretation of the sentences heard. This
shows that Brazilian preschoolers can use prosodic information to constrain their parsing.

Brazilian Portuguese-learning children's performance in the present task is comparable to the performance of French-learning children of the same age in Kolberg et al.'s (2021) study. In both studies, the results showed time clusters with a significant difference between conditions, and a significant difference in overall looking times in the t-test analysis (see Kolberg et al. 2021 for more details on the French results). The similarities between these results suggest that children can rely on prosodic boundary information for sentence parsing similarly in languages in which prosodic cues are mostly used to mark phrase boundaries, such as French, and in languages in which prosodic cues are more widely used for different aspects of language other than to mark phrase boundaries, such as Brazilian Portuguese. We therefore provide cross-linguistic evidence for the role of phrasal prosody in syntactic acquisition in young children.

Nevertheless, when comparing the time course of the effects in the present results to the French results of Kolberg et al. (2021), we notice that Brazilian children seem to take longer to integrate prosodic boundary cues in their parsing decisions than their French peers. The effect of prosody in French manifested earlier (with the first significant time cluster observed between 1920 ms and 3820 ms from the onset of the test trial, and the second one between 3980 ms and 8080 ms), in test trials of the exact same duration, featuring the same video stimuli and a comparable time of appearance of word onsets in the test sentences. This might point to a potential cross-linguistic difference between the speed of processing of prosodic boundary cues by French and Brazilian children. As stated in the introduction, the fact that prosodic information signals more than just prosodic boundaries in Brazilian Portuguese might mean that prosodic cues are more ambiguous to young children learning this language. Brazilian children may take longer to learn the various linguistic functions conveyed by prosody in their language, which
could affect their ability to incorporate prosodic boundary information into their parsing decisions. In contrast, French children's faster performance may result from the more limited range of prosodic functions in French, where prosody primarily serves to mark phrase boundaries, thus reducing potential ambiguities.

There are, however, other possible explanations for these results. First, the eye-trackers used in the two studies differed in precision. Kolberg et al. (2021) used an Eyelink 1000, which has better spatial and temporal resolution (each time point was collected every 2 ms) than the Gazepoint eye-tracker used in our Brazilian study (each time point was collected every 16 ms on average). The lower precision of Gazepoint could be at least partially responsible for creating this apparent delay in speed of processing in the results of Brazilian children. But the difference found between the French and Brazilian studies might be too large (around 4 seconds) to be explained solely through a difference in eyetracking precision.

Another difference between the studies in French and in Brazilian Portuguese is that while Kolberg et al. (2021) tested mostly children coming from middle-high to high SES families at the lab (in the city center of Paris), the children in Brazil were tested in daycares and preschools with children coming from middle-low to low SES families (in the city center of Campinas). Given that language acquisition is subject to socioeconomic (SES) differences, it is possible that the differences in speed of processing we found between French and Brazilian preschoolers is a consequence of these differences. Children from low SES families are generally less frequently exposed to speech and have a smaller vocabulary than children from high SES families (see e.g., Fernald, Marchman, & Weisleder, 2013; Golinkoff et al., 2019; Hart & Risley, 1995; Levine et al., 2020; Marchman & Fernald, 2008; Scaff, Fibla, & Cristia, 2023). Children who are less
frequently exposed to speech also tend to be slower to process sentences than the ones
who are more frequently exposed to speech (see e.g., Marchman & Fernald, 2008).

Finally, another explanation for the discrepancy between French and Brazilian
results may lie in the differing testing environments. French children underwent testing
within a sound-attenuated booth, shielding them from external noise and visual
distractions. In contrast, Brazilian children were tested in open classrooms, with limited
isolation from ambient noise, aside from the headphones used to listen to the test
sentences. Additionally, there was minimal control over external visual stimuli, such as
classroom furniture. This potentially more distracting environment could have impacted
Brazilian children's attention to the task, potentially contributing to the differences in
processing speed observed.

In summary, while our results suggest a cross-linguistic difference in the speed of
prosodic cue integration during parsing—likely related to the number of competing
linguistic functions signaled by prosody in a given language—further research is needed
to confirm this finding. Future studies should involve children from similar SES
backgrounds, comparing their performance in experiments conducted under the same
conditions, using consistent equipment, items, and visual stimuli across the two languages
tested. This is certainly not an easy task to accomplish.

Our current results also suggest that Brazilian-Portuguese-speaking 3-to-4-year-
olds understand ellipsis sentences, which means that they can recover an elided phrase
through its identity relationship with a preceding phrase. This is in line with previous
studies showing that children understand and produce ellipsis constructions from around
three years of age (Foley et al., 2003, and Postman et al., 1997, in English; Lindenbergh,
Van Hout & Hollebrandse, 2015, in Dutch; among others), and adds evidence for a less-
studied type of ellipsis, namely stripping.
Although the looking data in both Kolberg et al. (2021) and in our current study showed that children in the ellipsis condition interpreted the sentences differently from children in the transitive condition, none of these studies found a significant difference between conditions in the pointing analysis. This could be explained by the fact that the pointing tasks in these studies were rather complex. As mentioned in Kolberg et al. (2021), pointing tasks are usually harder for young children because they demand an overt judgment. This requires not only a higher memory load (since children need to recover the sentence heard during the test trial), but also better inhibitory control and capacity for overtly judging the meaning of the sentences and identifying which of the presented contexts better describe them. In contrast to previous studies that succeeded with pointing tasks in young children, where participants were typically tasked with identifying referents of novel verbs or nouns following simple requests such as “show me the *blick* /the one who is *blicking*”, our task was more intricate. We asked children to retain a complex sentence in memory and map it to a dynamic scene. Our instruction was also more “abstract” and less straightforward, as we asked children to point at the video “the lady was talking about”. In this context, the looking task appears to be more manageable for children, as it captures their real-time interpretation without the need for an overt judgment of the sentence. This approach relies on children's natural ability to closely align visual and auditory contexts (see e.g., Golinkoff et. al., 1987).

The results of this study add new evidence to the hypothesis that young children can use prosody as a cue for grouping words into syntactic constituents within a sentence and therefore to guide their syntactic analysis. They also contribute to the investigation of the universality of this hypothesis, by investigating children learning Brazilian Portuguese, a language that had not yet been studied for this purpose and differs from French in the way it uses prosodic information. The present study contributes to the
hypothesis that phrasal prosody is an important cue for the beginning of language acquisition, and that young children can rely on it to uncover the syntactic structure of the sentences they hear.

## Acknowledgements

This work was supported by a PhD fellowship from CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil) [Grants 88881.188983/2018-01 and 88882.329599/2018-01] to the first author; by a Research Grant from the Fyssen Foundation to the second author [Grant Eotp RH03J20AFO04 H03R8240]; and by grants from the Fondation de France, and the French National Research Agency ANR [grant numbers: ANR-13-APPR-0012 LangLearn, ANR-17-CE28-0007-01 LangAge, and ANR-17-EURE-0017 FrontCog]. It has also received financial support from the CNRS through the MITI interdisciplinary programs, and from Sciences Po – Université Paris Cité (Fonds Investissement d'Avenir) awarded to the second author.

We sincerely thank the reviewers of this paper for their thoughtful suggestions, which have helped us improve the clarity of our paper.

## Disclosure statement

The authors report there are no competing interests to declare.

## Data availability statement

The method, data analysis and criteria for exclusion of participants were pre-registered on the OSF (Open Science Framework) database before running the study. The materials, collected data, data analysis and additional exploratory analyses are freely available to readers at https://osf.io/98cmu/?view_only=9383d5ea4f2a40c0860171ab7f41c222

## References

Abboub, N., Nazzi, T., & Gervain, J. (2016). Prosodic grouping at birth. *Brain and Language, 162*, 46–59. https://doi.org/10.1016/j.bandl.2016.08.002
Babineau, M., Barbir, M., de Carvalho, A., Havron, N., Dautriche, I. & Christophe, A. (2024). Syntactic bootstrapping as a mechanism for language learning. *Nature Reviews Psychology, 3*, 463-474. https://doi.org/10.1038/s44159-024-00317-w

Bailey, T. M., & Plunkett, K. (1998). Learning prosody: Infants' learning of two word stress rhythms. *Infant Behavior and Development, 21*, 172. https://doi.org/10.1016/s0163-6383(98)91387-x

Barss, A. (Ed.). (2003). *Anaphora: A reference guide* (1st ed.). Wiley Blackwell.

Choi, Y., & Mazuka, R. (2003). Young children's use of prosody in sentence parsing. *Journal of Psycholinguistic Research, 32*(2), 197-217. https://doi.org/10.1023/a:1022400424874

Christophe, A., Dautriche, I., de Carvalho, A., & Brusini, P. (2016). Bootstrapping the syntactic bootstrapper. In J. Scott & D. Waughtal (Eds.), *Proceedings of the 40th Annual Boston University Conference on Language Development* (pp. 75-88). Sommerville, MA: Cascadilla Press.

Christophe, A., Millotte, S., Bernal, S., & Lidz, J. (2008). Bootstrapping lexical and syntactic acquisition. *Language and Speech, 51*(1-2), 61-75. https://doi.org/10.1177/00238309080510010501

Dautriche, I., Cristia, A., Brusini, P., Yuan, S., Fisher, C., & Christophe, A. (2014). Toddlers Default to Canonical Surface-to-Meaning Mapping When Learning Verbs. *Child Development, 85*(3), 1168-1180. https://doi.org/10.1111/cdev.12164

de Carvalho, A., Dautriche, I., & Christophe, A. (2016a). Preschoolers use phrasal prosody online to constrain syntactic analysis. *Developmental Science, 19*(2), 235-250. https://doi.org/10.1111/desc.12300

de Carvalho, A., Dautriche, I., Lin, I., & Christophe, A. (2017). Phrasal prosody constrains syntactic analysis in toddlers. *Cognition, 163*, 67-79. https://doi.org/10.1016/j.cognition.2017.02.018

de Carvalho, A., Dautriche, I., Millotte, S., & Christophe, A. (2018). Early perception of phrasal prosody and its role in syntactic and lexical acquisition. In P. Prieto & N. Esteve-Gibert (Eds.), *The Development of Prosody in First Language Acquisition* (pp. 17-35). John Benjamins Publishing Company. https://doi.org/10.1075/tilar.23.02car
de Carvalho, A., He, A. X., Lidz, J., & Christophe, A. (2019). Prosody and function words cue the acquisition of word meanings in 18-Month-Old infants. *Psychological Science*, 30(3), 319-332. https://doi.org/10.1177/0956797618814131

de Carvalho, A., Lidz, J., Tieu, L., Bleam, T., & Christophe, A. (2016b). English-speaking preschoolers can use phrasal prosody for syntactic parsing. *Journal of the Acoustical Society of America*, 139(6), EL216-EL222. https://doi.org/10.1121/1.4954385

Dink, J. W., & Ferguson, B. (2016). *eyetrackingR: An R Library for eye-tracking data analysis*. Retrieved from http://www.eyetrackingr.com

Esteve-Gibert, N., Lœvenbruck, H., Dohen, M., & d'Imperio, M. (2022). Pre-schoolers use head gestures rather than prosodic cues to highlight important information in speech. *Developmental science*, 25(1), e13154. doi:10.1111/desc.13154

Fernald, A., Marchman, V. A., & Weisleder, A. (2013). SES differences in language processing skill and vocabulary are evident at 18 months. *Developmental science*, 16(2), 234-248.

Féry, C. (2001). Focus and phrasing in French. *Audiatur vox sapientiae. A festschrift for Arnim von Stechow*, 153-181.

Foley, C., Nuñez Del Prado, Z., Barbier, I., & Lust, B. (2003). Knowledge of variable binding in VP-ellipsis: Language acquisition research and theory converge. *Syntax*, 6(1), 52-83. https://doi.org/10.1111/1467-9612.00056

Gervain, J., & Werker, J. F. (2013). Prosody cues word order in 7-month-old bilingual infants. *Nature Communications*, 4(1), 1490. https://doi.org/10.1038/ncomms2430

Golinkoff, R. M., Hirsh-Pasek, K., Cauley, K. M., & Gordon, L. (1987). The eyes have it: Lexical and syntactic comprehension in a new paradigm. *Journal of child language*, 14(1), 23-45. https://doi.org/10.1017/S030500090001271X

Golinkoff, R. M., Hoff, E., Rowe, M. L., Tamis-LeMonda, C. S., & Hirsh-Pasek, K. (2019). Language matters: Denying the existence of the 30-million-word gap has serious consequences. *Child development*, 90(3), 985-992.

Gout, A., Christophe, A., & Morgan, J. L. (2004). Phonological phrase boundaries constrain lexical access: II. Infant data. *Journal of Memory and Language*, 51(4), 548-567. https://doi.org/10.1016/j.jml.2004.07.002

Graf Estes, K., & Bowen, S. (2013). Learning about sounds contributes to learning about words: Effects of prosody and phonotactics on infant word learning. *Journal of*
*Experimental Child Psychology*, 114(3), 405-417.
https://doi.org/10.1016/j.jecp.2012.10.002

Gutman, A., Dautriche, I., Crabbé, B., & Christophe, A. (2015). Bootstrapping the syntactic bootstrapper: Probabilistic labeling of prosodic phrases. *Language Acquisition*, 22(3), 285-309. https://doi.org/10.1080/10489223.2014.971956

Hart, B., & Risley, T. R. (1995). *Meaningful differences in the everyday experience of young American children*. Paul H Brookes Publishing.

Hawthorne, K., & Gerken, L. A. (2014). From pauses to clauses: Prosody facilitates learning of syntactic constituency. *Cognition*, 133(2), 420-428.
https://doi.org/10.1016/j.cognition.2014.07.013

Hawthorne, K., Mazuka, R., & Gerken, L. A. (2015). The acoustic salience of prosody trumps infants' acquired knowledge of language-specific prosodic patterns. *Journal of Memory and Language*, 82, 105-117.
https://doi.org/10.1016/j.jml.2015.03.005

Hirsh-Pasek, K., Kemler Nelson, D. G., Jusczyk, P. W., Cassidy, K. W., Druss, B., & Kennedy, L. (1987). Clauses are perceptual units for young infants. *Cognition*, 26(3), 269-286. https://doi.org/10.1016/s0010-0277(87)80002-1

Höhle, B., Weissenborn, J., Schmitz, M., & Ischebeck, A. (2001). Discovering word order regularities: The role of prosodic information for early parameter setting. In J. Weissenborn & B. Höhle (Eds.), *Approaches to Bootstrapping: Phonological, Lexical, Syntactic and Neurophysiological Aspects of Early Language Acquisition* (pp. 246-263). John Benjamins.

Johnson, E. K., & Jusczyk, P. W. (2001). Word segmentation by 8-month-olds: When speech cues count more than statistics. *Journal of Memory and Language*, 44(4), 548-567. https://doi.org/10.1006/jmla.2000.2755

Johnson, E. K. (2008). Infants use prosodically conditioned acoustic-phonetic cues to extract words from speech. *The Journal of the Acoustical Society of America*, 123(6), 144-148. https://doi.org/10.1121/1.2908407

Johnson, E. K., & Seidl, A. (2008). Clause segmentation by 6-month-old infants: A crosslinguistic perspective. *Infancy*, 13(5), 440-455.
https://doi.org/10.1080/15250000802329321

Jusczyk, P. W., Cutler, A., & Redanz, N. J. (1993). Infants' preference for the predominant stress patterns of English words. *Child Development*, 64(3), 675-687.
https://doi.org/10.2307/1131210
Jusczyk, P. W., Hirsh-Pasek, K., Kemler Nelson, D. G., Kennedy, L. J., Woodward, A., & Piwoz, J. (1992). Perception of acoustic correlates of major phrasal units by young infants. *Cognitive Psychology, 24*(2), 252–293.
https://doi.org/10.1016/0010-0285(92)90009-q

Kidd, E., & Garcia, R. (2022). How diverse is child language acquisition research? *First Language, 42*(6), 703-735.

Kolberg, L., de Carvalho, A., Babineau, M., Havron, N., Fiévet, A. C., Abaurre, B., & Christophe, A. (2021). “The tiger is hitting! the duck too!” 3-year-olds can use prosodic information to constrain their interpretation of ellipsis. *Cognition, 213*, 104626. https://doi.org/10.1016/j.cognition.2021.104626

Ladd, D. R. (2008). *Intonational phonology*. Cambridge University Press.

Lee, G., Shin, D. J., & Garcia, M. T. M. (2019). Perception of lexical stress and sentence focus by Korean-speaking and Spanish-speaking L2 learners of English. *Language Sciences, 72*, 36-49.

Levine, D., Pace, A., Luo, R., Hirsh-Pasek, K., Golinkoff, R. M., de Villiers, J., Iglesias, A., & Wilson, M. S. (2020). Evaluating socioeconomic gaps in preschoolers’ vocabulary, syntax and language process skills with the Quick Interactive Language Screener (QUILS). *Early Childhood Research Quarterly, 50*, 114-128.

Lindenbergh, C., Van Hout, A., & Hollebrandse, B. (2015). Extending ellipsis research: The acquisition of sluicing in Dutch. In E. Grillo, K. Jepson, & M. LaMendola (Eds.), *BUCLD 39 Online Proceedings Supplement*. Boston, MA. Retrieved from http://www.bu.edu/bucld/supplementvol39/

Mandel, D. R., Jusczyk, P. W., & Kemler Nelson, D. G. (1994). Does sentential prosody help infants organize and remember speech information? *Cognition, 53*(2), 155-180. https://doi.org/10.1016/0010-0277(94)90069-8

Marchman, V. A., & Fernald, A. (2008). Speed of word recognition and vocabulary knowledge in infancy predict cognitive and language outcomes in later childhood. *Developmental science, 11*(3), 9-16.

Maris, E., & Oostenveld, R. (2007). Nonparametric statistical testing of EEG- and MEG data. *Journal of Neuroscience Methods, 164*(1), 177-190.
https://doi.org/10.1016/j.jneumeth.2007.03.024

Massicotte-Laforge, S., & Shi, R. (2015). The role of prosody in infants' early syntactic analysis and grammatical categorization. *The Journal of the Acoustical Society of America, 138*(4), 441–446. https://doi.org/10.1121/1.4934551
Massicotte-Laforge, S., & Shi, R. (2020). Is prosodic information alone sufficient for guiding early grammatical acquisition? *The Journal of the Acoustical Society of America*, 147(3), 295–300. https://doi.org/10.1121/10.0000887

Mehler, J., Jusczyk, P., Lambertz, G., Halsted, N., Bertoncini, J., & Amiel-Tison, C. (1988). A precursor of language acquisition in young infants. *Cognition*, 29(2), 143–178. https://doi.org/10.1016/0010-0277(88)90035-2

Morgan, J. L., & Demuth, K. (Eds.). (1996). *Signal to syntax: Bootstrapping from speech to grammar in early acquisition*. Lawrence Erlbaum Associates.

Morgan, J. L., & Saffran, J. R. (1995). Emerging integration of sequential and suprasegmental information in preverbal speech segmentation. *Child Development*, 66(4), 911–936. https://doi.org/10.2307/1131789

Nespor, M., & Vogel, I. (1986). *Prosodic phonology*. Foris.

van Ommen, S., Boll-Avetisyan, N., Larraza, S., Wellmann, C., Bijeljac-Babic, R., Höhle, B., & Nazzi, T. (2020). Language-specific prosodic acquisition: A comparison of phrase boundary perception by French- and German-learning infants. *Journal of Memory and Language*, 112, 1–16. https://doi.org/10.1016/j.jml.2020.104108

Postman, W., Foley, C., Santelmann, L., & Lust, B. (1997). Evidence for Strong Continuity: New experimental results from children’s acquisition of VP-ellipsis and bound variable structures. *MIT Working Papers in Linguistics*, 31, 327–344. Retrieved from http://mitwpl.mit.edu/

R Core Team. (2017). *R: A Language and Environment for Statistical Computing*. https://www.R-project.org/

Ramachers, S., Brouwer, S., & Fikkert, P. (2017). How native prosody affects pitch processing during word learning in Limburgian and Dutch toddlers and adults. *Frontiers in Psychology*, 8, 1–20. https://doi.org/10.3389/fpsyg.2017.01652

Ross, J. R. (1969). Guess who? In R. Binnick, A. Davidson, G. Green, & J. Morgan (Eds.), *Papers from the 5th Regional Meeting of the Chicago Linguistic Society* (p. 252-286). Chicago, IL: Chicago Linguistic Society.

Scaff, C., Fibla, L., & Cristia, A. (2023). Factors structuring lexical development in toddlers: The effects of parental education, language exposure, and age. *Journal of Child Language*, 50(3), 757-777.

Selkirk, E. (1984). *Phonology and syntax. The relation between sound and structure*. Cambridge, MA: The MIT Press.
Shukla, M., White, K. S., & Aslin, R. N. (2011). Prosody guides the rapid mapping of auditory word forms onto visual objects in 6-mo-old infants. *Proceedings of the National Academy of Sciences*, 108(15), 6038–6043. https://doi.org/10.1073/pnas.1017617108

Snedeker, J., & Trueswell, J. (2001). *Unheeded cues: Prosody and syntactic ambiguity in mother-child communication* [Conference presentation]. The 26th Annual Boston University Conference on Language Development (BUCLD), Boston, MA, United States.

Snedeker, J., & Yuan, S. (2008). Effects of prosodic and lexical constraints on parsing in young children (and adults). *Journal of Memory and Language*, 58(2), 574–608. https://doi.org/10.1016/j.jml.2007.08.001

Soderstrom, M., Seidl, A., Kemler Nelson, D. G., & Jusczyk, P. W. (2003). The prosodic bootstrapping of phrases: Evidence from prelinguistic infants. *Journal of Memory and Language*, 49(2), 249–267. https://doi.org/10.1016/s0749-596x(03)00024-x

Wellmann, C., Holzgrefe, J., Truckenbrodt, H., Wartenburger, I., & Höhle, B. (2012). How each prosodic boundary cue matters: Evidence from German infants. *Frontiers in Psychology*, 3, 1–13. https://doi.org/10.3389/fpsyg.2012.00580

## Appendix

<table><caption>Table A1. Description of test videos.</caption><thead><tr><td>Action</td><td>Two-agent video</td><td>One-agent video</td></tr></thead><tbody><tr><td>Eat</td><td>A tiger and a dinosaur repeatedly poke a duck (laying on a plate) with a fork</td><td>A tiger repeatedly pokes a dinosaur (laying on a plate beside a duck) with a fork</td></tr><tr><td>Push</td><td>A bunny and a monkey push a dinosaur sitting on a trolley back and forth to each other</td><td>A monkey pushes a bunny and a dinosaur on a trolley from one side of the screen to the other</td></tr><tr><td>Poke</td><td>A tiger and a duck simultaneously poke a bunny with a stick</td><td>A tiger alternately pokes a bunny and a duck with a stick</td></tr><tr><td>Carry</td><td>A duck and a dinosaur carry a present each while gently swinging from side to side</td><td>A duck carries a present over one wing and a dinosaur over the other while gently swinging from side to side</td></tr></tbody></table>
<table><caption>Table A2. Video design. A single training phase was followed by four test phases, one for each action. The order of the test phases and the side of appearance of each video is randomized.</caption><thead><tr><th rowspan="2">Trial</th><th colspan="2">Video stimuli</th><th rowspan="2">Audio stimuli</th><th rowspan="2">Time</th></tr><tr><th>Left</th><th>Right</th></tr></thead><tbody><tr><td>Character introduction</td><td colspan="2">Characters appear on the screen (5s each)</td><td>Characters named once (e.g., "Olha! É o tigre!")</td><td>30s</td></tr><tr><td>Interval</td><td colspan="2">Laughing baby</td><td>Laughing baby</td><td>5s</td></tr><tr><td>Fixation circle</td><td colspan="2">Fixation circle</td><td>no audio</td><td>1s</td></tr><tr><td colspan="5" style="text-align: center; font-weight: bold;">Training phase</td></tr><tr><td>Preview trial</td><td>Bunny jumping</td><td></td><td>"Ei, olha só!"</td><td>5s</td></tr><tr><td>Interval</td><td colspan="2">Blank screen</td><td>no audio</td><td>1s</td></tr><tr><td>Preview trial</td><td></td><td>Bunny and monkey playing</td><td>"Ei, olha só!"</td><td>5s</td></tr><tr><td>Fixation circle</td><td colspan="2">Fixation circle</td><td>no audio</td><td>1s</td></tr><tr><td>Contrast trial</td><td>Bunny jumping</td><td>Bunny and monkey playing</td><td>"Ei, olha! Ta vendo isso?"</td><td>5s</td></tr><tr><td>Audio prompt</td><td colspan="2">Fixation circle</td><td>"Olha! O coelho vai pular! O pato também!"</td><td>3s</td></tr><tr><td>Test trial</td><td>Bunny jumping</td><td>Bunny and monkey playing</td><td>"Ei, olha! O coelho ta pulando! Ta vendo? O coelho ta pulando!"</td><td>12s</td></tr><tr><td>Pointing trial</td><td>Bunny jumping (paused)</td><td>Bunny and monkey playing (paused)</td><td>No audio</td><td>User controlled</td></tr><tr><td>Interval</td><td colspan="2">Laughing baby</td><td>Laughing baby</td><td>5s</td></tr><tr><td>Fixation circle</td><td colspan="2">Fixation circle</td><td>no audio</td><td>1s</td></tr><tr><td colspan="5" style="text-align: center; font-weight: bold;">Test phase</td></tr><tr><td>Intro test phase</td><td colspan="2">Tiger eating duck with a fork</td><td>"Olha! Um tigre e um pato! Ei, ele ta comendo!"</td><td>10s</td></tr><tr><td>Interval</td><td colspan="2">Blank screen</td><td>no audio</td><td>3s</td></tr><tr><td>Preview trial</td><td></td><td>Tiger and dinosaur eating duck</td><td>"Olha! Ta vendo isso?"</td><td>9s</td></tr><tr><td>Interval</td><td colspan="2">Blank screen</td><td>no audio</td><td>1s</td></tr><tr><td>Preview trial</td><td>Tiger eating dinosaur</td><td></td><td>"Olha! Ta vendo isso?"</td><td>9s</td></tr></tbody></table>
<table><thead><tr><th rowspan="2">Trial</th><th colspan="2">Video stimuli</th><th rowspan="2">Audio stimuli</th><th rowspan="2">Time</th></tr><tr><th>Left</th><th>Right</th></tr></thead><tbody><tr><td>Fixation circle</td><td colspan="2">Fixation circle</td><td>no audio</td><td>1s</td></tr><tr><td>Contrast trial</td><td>Tiger eating dinosaur</td><td>Tiger and dinosaur eating duck</td><td>"Olha só! Nossa, que legal!"</td><td>9s</td></tr><tr><td>Audio prompt</td><td colspan="2">Fixation circle</td><td>"Veja só: o tigre vai comer (.) o dinossauro também!"</td><td>~5s</td></tr><tr><td>Test trial</td><td>Tiger eating dinosaur</td><td>Tiger and dinosaur eating duck</td><td>"Ei, olha! O tigre ta comendo (.) o dinossauro também! Ta vendo? O tigre ta comendo (.) o dinossauro também!"</td><td>12s</td></tr><tr><td>Pointing trial</td><td>Tiger eating dinosaur (paused)</td><td>Tiger and dinosaur eating duck (paused)</td><td>no audio</td><td>User controlled</td></tr><tr><td>Interval</td><td colspan="2">Laughing baby</td><td>Laughing baby</td><td>5s</td></tr><tr><td>Fixation circle</td><td colspan="2">Fixation circle</td><td>no audio</td><td>1s</td></tr></tbody></table>

List of tables and figures

Tables

<table><caption>Table 1. Mean duration (in ms) for different segments around prosodic boundaries for both conditions: stripping vs transitive sentences.</caption><thead><tr><th rowspan="2"></th><th colspan="2">Stripping sentences<br>(e.g. [o tigre ta cutucando]<br>[o pato também])</th><th colspan="2">Transitive sentences<br>(e.g. [o tigre] [ta cutucando<br>o pato também])</th><th rowspan="2">t-value<br>(p)</th></tr><tr><th>Duration<br>(ms)</th><th>SD</th><th>Duration<br>(ms)</th><th>SD</th></tr></thead><tbody><tr><td>Rhyme of 1<sup>st</sup> noun<br>(e.g. t[igre])</td><td>281</td><td>24</td><td>567</td><td>60</td><td>-12.486<br>(**p < 0.001)</td></tr><tr><td>Rhyme of verb<br>(e.g. cutuc[ando])</td><td>454</td><td>45</td><td>254</td><td>17</td><td>11.829<br>(**p < 0.001)</td></tr><tr><td>Pause between<br>verb and 2<sup>nd</sup> noun</td><td>451</td><td>63</td><td>0</td><td>0</td><td></td></tr></tbody></table>
<table><caption>Table 2. Mean difference for F0 (in Hz) in different segments around the prosodic boundaries for both conditions: stripping vs transitive sentences.</caption><thead><tr><th rowspan="2"></th><th colspan="2">Stripping sentences</th><th colspan="2">Transitive sentences</th><th rowspan="2">t-value<br>(p)</th></tr><tr><th>F0<br>(in Hz)</th><th>SD</th><th>F0<br>(in Hz)</th><th>SD</th></tr></thead><tbody><tr><td>First vowel of verb<br>(e.g. t[a]) minus<br>last vowel of 1<sup>st</sup><br>noun (e.g., tigr[e])</td><td>30</td><td>23</td><td>-118</td><td>104</td><td>3.958<br>(**p = 0.001)</td></tr><tr><td>1<sup>st</sup> vowel of 2<sup>nd</sup><br>noun (e.g. p[a]to)<br>minus stressed<br>vowel of verb (e.g.,<br>cutuc[an]do)</td><td>-274</td><td>62</td><td>90</td><td>40</td><td>-11.175<br>(**p &lt; 0.001)</td></tr></tbody></table>

## Figures

<figure><img src="image_3.png" /><figcaption>Figure 1. Soundwave, pitch, and duration for a pair of sentences used in this experiment. A stripping sentence (“O tigre ta cutucando! O pato também!”) at the bottom and a transitive sentence (“O tigre ta cutucando o pato também!”) on top. The duration of each segment, averaged over all sentences from the four test trials, is indicated on the bottom. Given the coarticulation between the final vowel of the verb and the article of the second noun, we chose to split this vowel midway to calculate the average duration of each segment, namely, the main verb and the determiner + noun combination.</figcaption></figure>
<figure><img src="image_4.png" /><figcaption>Figure 2. Structure of a test trial. The clock icon followed by the number illustrates how long each video/grey screen was displayed.</figcaption></figure>
<figure><img src="image_5.png" /><figcaption>Figure 3. Proportion of looks towards the two-agent action through the entire test trial (12 seconds in each trial) in the ellipsis (red line) and transitive (blue line) condition. The gray rectangles show the significant time clusters and their p-values. The average time of appearance for each word in the test sentences is indicated in the gray boxes below the graph (the upper boxes show the average time for ellipsis sentences, and the boxes below show the average time for transitive sentences).</figcaption></figure>
<figure><img src="image_6.png" /></figure>

Figure 4. Average proportion of looking time towards the two-agent action in the ellipsis (red box) and transitive (blue box) condition. Each black dot represents the average looking time for one participant. The white dashed lines show the average pointing for each condition (.59 for ellipsis sentences, and .50 for transitive sentences). The lower and upper hinges correspond to the first and third quartiles, and the top and bottom whiskers denote the maximum and minimum value, respectively. The outliers (i.e., the black dots which are distant from the whiskers) were not removed from the reported analyses.
<figure><img src="image_7.png" /><figcaption>Figure 5. Average proportion of pointing towards the two-agent action. The white dashed lines show the mean for each condition (.65 for the ellipsis condition (red bar) and .53 for the transitive condition (blue bar)). Each black dot represents the average proportion of pointing for one participant. The lower and upper hinges correspond to the first and third quartiles, and the top and bottom whiskers denote the maximum and minimum value, respectively.</figcaption></figure>