1. Bosch & Sebastián-Gallés Simultaneous Bilingualism and the Perception of a Language-Specific Vowel Contrast in the First Year of Life

2. Introduction: This research explores the behaviour of monolingual Spanish and monolingual Catalan infants, in order to analyze their perception of native-sound contrasts. Because other research has been done on monosyllabic stimuli, this study used a more complex structure (CV 1 CV 2 ). The vowel contrast studied was /e/ and /ε/.

3. Hypotheses Experiment 1: All three subgroups would perceive the vowel contrast at 4 months of age. Experiment 2: However, at the age of 8 months, only the monolingual Catalan group should perceive the vowel contrast.

4. Experiment 1: Subjects: 36 infants of 4 months of age were recruited 3 groups of 12 infants: Catalan monolinguals Spanish monolinguals Catalan-Spanish bilinguals The experimenters were interested in the 2 monolingual groups.

5. Stimuli: The contrastive category that is studied is the Catalan vowel contrast /e/ and /ε/ (two midfront vowels) in a CV 1 CV 2 context. In determining the infants’ discrimination capacities, the experimenters: placed the vowel in the first stressed syllable of a pseudoword; used several tokens from five different females (variability).

6. Stimuli (cont): Pseudowords [‘dV.  i] with V= /e/ and /ε/. 18 tokens were recorded from 5 females (native speakers of Catalan and Spanish) Motherese style

7. Stimuli: (cont) How were the stimuli chosen? Acoustic perspective vs phonetic perspective Formants of each token

8. Procedure Head-turn preference procedure An image on the center monitor appears to capture the infant’s attention and to have him focused. A speech stimulus is presented to the infant from either the left or right loudspeaker. If there is a change in the speech stimulus, the infant will turn his head towards the stimulus. If the child turns his head on the right side, a picture will appear on the monitor (reinforcement). (source: http://www.psych.ubc.ca/~jwlabmgr/meth_cond.html)

9. Procedure (cont): 1) familiarization phase based on the infants’ looking behavior; half of the infants were familiarized with [‘de  i], the other half with [‘dε  i] each infant had to accumulate 2 minutes of sustained attention 2) testing phase listening of contrastive materials; there is discrimination when there is differential attention time (greater listening time) between similar and novel materials; the similar materials are the tokens presented in the familiarization phase.

10. Familiarization phase: Structure of a trial: Two sets of 6 tokens from the same vowel category were presented to the infant. Up to 6 trials of 25 seconds were needed to obtain a 2 minute sustained attention. Group 1Group 2 [‘de  i] [‘de  i][‘dε  i] [‘dε  i] x2 x2x2x2

11. Testing Phase: New tokens of the same category of vowels from the familiarization phase are presented to the infant; Contrastive tokens are presented to both groups. Infants react to those tokens by staring

12. Results Experiment 1: Mean attention time:

13. Results Experiment 1 Hypothesis confirmed: An infant of 4 months can discriminate the vowel contrast of /e/ and /ε/ within the first syllable of a disyllabic CVCV stimulus. They can also normalize for talker and token variability. This shows that at 4 months, the ambient language still has no effect on their ability to discriminate vowel contrasts.

14. Experiment 2 For the second experiment, Bosch and Sebastián-Gallés were interested in analyzing the impact that linguistic exposure would have on eight-month-old infants’ ability to perceive vowel contrasts.

15. Hypotheses: Since these two categories are present only in Catalan, eight-month-old infants coming from Catalan-speaking families should discriminate them. However, infants coming from Spanish- speaking families should not be able to perceive the contrast as easily since it is not present in their language.

16. Subjects & Stimuli: Subjects: 8 month old infants 3 groups participated in this experiment: Catalan monolinguals Spanish monolinguals Catalan-Spanish bilinguals Stimuli: Same vowel contrasts (/e/ and /ε/) from Experiment 1.

17. Results Experiment 2: Mean attention time

18. Results Experiment 2 (cont): The Catalan monolingual group, which is exposed to this vowel contrast in its linguistic environment, has no problem perceiving it. On the other hand, eight-month-old infants from Spanish monolingual environment might only perceive the two vowels as being different ways of producing the same vowel.

19. Discussion: The results of both experiments confirm the following predictions : At four months, babies from both Catalan monolinguial and Spanish monolingual environments can discriminate the Catalan vowel contrast /e/-/ε/. At eight months, only infants from the Catalan monolingual environment can perceive the contrast, showing that linguistic exposure might alter these language-general initial sensitivities.

20. Let’s Wrap it Up!!! The experiments have shown with different contrasts that at the age of 4 months, infants are universal listeners. We can also see that around 8 months of age, infants start to lose the sensitivity to discriminate languages and they become more sensitive to the contrasts in their mother tongue.