Development of non-native vowel discrimination: Improvement without exposure

Area of Science:

• Linguistics
• Developmental Psychology
• Speech Perception

Background:

• Infants' ability to perceive speech sounds is crucial for language acquisition.
• Early language exposure shapes phonetic discrimination abilities.
• The perception of non-native speech sounds can be challenging for infants.

Purpose of the Study:

• To investigate Japanese infants' and adults' ability to discriminate specific German vowel contrasts not present in Japanese.
• To examine developmental changes in non-native speech sound discrimination in infants.
• To assess the impact of age on the perception of phonemic contrasts absent in the native language.

Main Methods:

• Visual habituation-dishabituation paradigm used to test auditory discrimination.
• Tested Japanese 4.5- and 10-month-old infants on three German vowel pairs.
• Also tested Japanese adults' discrimination of the same German vowel pairs.

Main Results:

• 4.5-month-old infants discriminated the German /bu:k/-/by:k/ contrast.
• 10-month-old infants discriminated the German /bi:k/-/be:k/ contrast.
• Japanese adults accurately discriminated all tested German vowel pairs.

Conclusions:

• Discriminating non-native speech contrasts is not universally easy for infants, even at young ages.
• Infants' ability to discriminate non-native contrasts can improve with age, independent of direct language exposure.
• This suggests an innate developmental trajectory for processing specific phonetic distinctions.