PaPI 2005 (Barcelona, June) The perception of stress patterns by Spanish and Catalan infants Ferran Pons (University of British Columbia) Laura Bosch (Universitat de Barcelona)

PaPI 2005 (Barcelona, June) Rhythmic properties of the input language  Infants’ early sensitivity to prosodic information (rhythm and intonation) in the prelexical stage: language discrimination studies  Stress as a cue to bootstrapping syntax  Stress as a cue to word segmentation: orientation towards the predominant stress pattern of the target language

PaPI 2005 (Barcelona, June) Previous data (I)  English-learning infants  Between 6 and 9 months of age  growing knowledge about the distribution of stress within words in the language Jusczyk, Cutler & Redanz (1993) 9 month-olds (but not 6 month-olds) prefer to listen to disyllabic trochees (real words, also low-pass filtered).

PaPI 2005 (Barcelona, June) Previous data (II)  Echols et al. (1997) SW grouping when pauses precede a strong syllable (WSW stimuli)  Höhle (2002) SW preference in German-learning infants (6 month-olds)

PaPI 2005 (Barcelona, June) Word segmentation in English  Around 90% content words (disyllabic) are trochaic; monosyllabic words are stressed.  Metrical segmentation strategy Stress cues can reliably be used for segmentation purposes, as they help infants find word boundaries Jusczyk et al. (1999): earlier segmentation for trochees than for iambs (10 ½ mo.) Houston et al. (2000): cross-language SW segmentation by 9 month-olds (English/Dutch)

PaPI 2005 (Barcelona, June) Word segmentation in English  Multiple cues to segmentation, although prosodic and statistical ones would be used before phonotactic and allophonic cues Mattys et al., 1999 Statistical regularities earlier than prosodic cues? Thiessen & Saffran (2003)

PaPI 2005 (Barcelona, June) Word segmentation in languages other than English  French: late word segmentation? Gout, 2001  9 month-olds do not segment iambic words (predominant pattern).  Dutch: SW words are not segmented by 7 ½ months of age, but by 9 months. Kuijpers et al., 1998  differences in the relative prominence of the SW foot between English and Dutch would explain the discrepancy These studies shed light on the generability of the metrical segmentation strategy

PaPI 2005 (Barcelona, June) Stress in Spanish  Most frequent word shape is disyllabic, but only around 65% of these words begin with a strong syllable.  Lexical stress is not fixed, but stress on the penultimate syllable is the predominant pattern.  Syllable weight is a relevant factor

PaPI 2005 (Barcelona, June) Stress in Catalan  Catalan, like Spanish, is also considered a trochaic language.  Lexical stress is variable.  Around 66% of disyllabic words are trochaic  Moraic throchee: minimal word pattern (Cabré, 1993)

PaPI 2005 (Barcelona, June) Infant data  assessing infants’ capacity to discriminate SW vs. WS patterns  exploring preferences in Spanish- learning and Catalan-learning infants

PaPI 2005 (Barcelona, June) Experiment 1: Discrimination  Material: CVCV stimuli Vowels: a, i, u Consonants: p, t, k, b, d, m, n, l Examples: buki, nila, luta, taki, datu… Lists: 8 different tokens, presented twice (trials’ length: 24”)

PaPI 2005 (Barcelona, June) Experiment 1: Discrimination  Procedure: Familiarization-preference procedure (adaptation from Jusczyk & Aslin 1995)  A 2-minute’s familiarization phase to trochaic or iambic lists followed by 4 test trials (2 same & 2 switch).  Participants: Sixteen 8 ½-month-old infants from a monolingual environment (Spanish or Catalan).

PaPI 2005 (Barcelona, June) Experiment 1: Discrimination  Results * * p =.022

PaPI 2005 (Barcelona, June) Experiment 1: Discrimination  Discussion: 8 ½ -month-old infants from Spanish or Catalan monolingual families are able to discriminate between trochaic and iambic disyllabic word shapes. This discrimination capacity, which is possibly present even at an earlier age, does not seem to have been modified by language exposure. Sensitivity to stress patterns is required if stress cues are to be used for word segmentation purposes.

PaPI 2005 (Barcelona, June) Experiment 2: Preference  Stress pattern preferences arise during the second semester of life from exposure to the ambient language, possibly after some words have already been segmented by means of statistical learning mechanisms applied to the continuous speech signal  Question: Will a trochaic bias be also present in the two Romance languages under study?

PaPI 2005 (Barcelona, June) Experiment 2: Preference  Hypothesis: As in the case of English-learning infants, 9 month-old infants, but not 6 month-olds, will show a preference for the dominant word stress pattern in their language (trochaic).

PaPI 2005 (Barcelona, June) Experiment 2a: Preference  Stimuli: 42 different disyllabic CVCV non-words, either trochaic or iambic (lists of 18 items (6x3) per trial).  Participants: 16 6-month-old Spanish monolingual infants month-old Catalan monolingual infants.

PaPI 2005 (Barcelona, June) Experiment 2a: Preference  Procedure: A slightly modified version of the Head-turn Preference Procedure (HPP) was used.  4 familiarization trials  12 test trials (6 trochaic & 6 iambic) Measures: Mean attention time to trochaic vs. iambic test trials

PaPI 2005 (Barcelona, June) Experiment 2a: Preference  Setting

PaPI 2005 (Barcelona, June) Experiment 2a: Preference  Results (6-month-olds)

PaPI 2005 (Barcelona, June) Experiment 2b: Preference  Participants: 16 9-month-old Spanish monolingual infants month-old Catalan monolingual infants.  Stimuli and procedure: The same as in experiment 2a. Setting: infants sat on their parents’ lap.

PaPI 2005 (Barcelona, June) Experiment 2b: Preference  Results (9-month-olds)

PaPI 2005 (Barcelona, June) Studies of preference (2 a & b)  Discussion Neither 6 month-old nor 9 month-old Catalan and Spanish infants showed a preference for the trochaic pattern. Acoustic analysis of the test stimuli revealed clear markers of stress that signaled trochaic versus iambic items (intensity, duration and pitch)

PaPI 2005 (Barcelona, June) Acoustic correlates of stress in test stimuli

PaPI 2005 (Barcelona, June) Studies of preference (2 a & b)  These results suggest that infants exposed to trochaic languages, such as Catalan or Spanish, which have nevertheless a less predominant stress pattern than English, may not develop an early sensitivity for this metrical property.  However, stress information may be linked to other properties (syllable structure, phonotactics…)  preference might then be observed and this information could be used for word segmentation purposes.

PaPI 2005 (Barcelona, June) Lexical stress and syllable weight  Quantity sensitive languages use syllable weight when assigning stress: Syllable weight hypothesis  preference for SW patterns would not emerge for words with a lax vowel in the stressed syllable Stress pattern hypothesis  preference for SW patterns before sensitivity to the principle of syllable weight

PaPI 2005 (Barcelona, June) Syllable weight studies  Turk, Jusczyk & Gerken (1995) SW preference in non-words, where S syllables were heavy or had a tense vowel. SW preference, even when S syllables were not heavy and had a lax vowel (stress pattern hypothesis) No preference for CV cvc / cv CVC (competing preferences cancelled each other)

PaPI 2005 (Barcelona, June) Syllable weight studies: conclusion  Turk, Jusczyk & Gerken (1995) In English, syllable weight is not a necessary component of the SW preference observed in infant studies Sensitivity to surface patterns and underlying linguistic principles seems to follow a separate time course in development

PaPI 2005 (Barcelona, June) Syllable weight in Spanish (based on LEXESP measures)  Spanish: CV·CVC words are mainly iambic (72%-84%, depending on the segments in the endings) -or 98% -on 84% -al 97% -el 97% -in, un < 60% CVC·CV words are mainly trochaic (95%)

PaPI 2005 (Barcelona, June) Experiment 3: Syllable weight  Procedure: A slightly modified version of HPP- Head-turn preference procedure was used.  Stimuli: 86 bisyllabic non-words CV·CVC, with either trochaic or iambic stress (lists of 12 items per trial).  4 familiarization trials  12 test trials (6 trochaic & 6 iambic)

PaPI 2005 (Barcelona, June) Experiment 3: Syllable weight  Participants: 16 9-month-old Spanish monolingual infants.  Hypothesis: If syllable weight is a relevant factor in lexical stress assignement, then 9-month-old infants will show a preference for the cv·CVC lists (iambic pattern) vs. CV·cvc lists (trochaic pattern, but highly infrequent in Spanish).

PaPI 2005 (Barcelona, June) Experiment 3: Syllable weight  Results (9-month-olds) * * p =.048

PaPI 2005 (Barcelona, June) Experiment 3: Syllable weight  Discussion By 9 months of age, infants have acquired knowledge about the most frequent stress pattern in cv·cvc words. They prefer cv·CVC iambic words, even though the language has a predominant trochaic pattern. At least in Spanish, syllable weight seems to be an important component linked to lexical knowledge and possibly relevant for stress segmentation.

PaPI 2005 (Barcelona, June) Final comments  The present results differ from previous work in English and support the syllable weight hypothesis.  Additional research exploring the preference for CVC·cv trochaic words in Spanish  strong support for the present hypothesis.  Segmentation studies with 9 month-old infants would reveal whether this information is used in word segmentation tasks.