Bosch

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Bosch Sebastián-Gallés

• Simultaneous Bilingualism and the Perception of a
  Language-Specific Vowel Contrast in the First
  Year of Life

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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 (CV1CV2).
• The vowel contrast studied was /e/ and /e/.

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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.

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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.

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Stimuli

• The contrastive category that is studied is the
  Catalan vowel contrast /e/ and /e/ (two midfront
  vowels) in a CV1CV2 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).

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Stimuli (cont)

• Pseudowords dV.?i with V /e/ and /e/.
• 18 tokens were recorded from 5 females (native
  speakers of Catalan and Spanish)
• Motherese style

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Stimuli (cont)

• How were the stimuli chosen?
• Acoustic perspective vs phonetic perspective
• Formants of each token

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Procedure

• Head-turn preference procedure
• An image on the center monitor appears to capture
  the infants 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/met
  h_cond.html)

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Procedure (cont)

• familiarization phase
• based on the infants looking behavior
• half of the infants were familiarized with
  de?i, the other half with de?i
• each infant had to accumulate 2 minutes of
  sustained attention
• 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.

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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 1 Group 2
• de?i de?i de?i de?i
• de?i de?i de?i de?i
• de?i de?i de?i de?i
• de?i de?i de?i de?i
• de?i de?i de?i de?i
• de?i de?i de?i de?i
• x2 x2 x2 x2

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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

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Results Experiment 1

• Mean attention time

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Results Experiment 1

• Hypothesis confirmed
• An infant of 4 months can discriminate the vowel
  contrast of /e/ and /e/ 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.

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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.

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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.

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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 /e/) from
  Experiment 1.

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Results Experiment 2

• Mean attention time

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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.

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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/-/e/.
• 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.

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Lets 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.