Speech sound learning depends on individuals' ability, not just experience

Area of Science:

• Neuroscience
• Linguistics
• Cognitive Science

Background:

• Bilingualism is hypothesized to enhance cognitive abilities, including speech sound learning.
• Understanding the neural basis of learning novel speech sounds is crucial for language acquisition research.

Purpose of the Study:

• To investigate whether phonetic experience with two languages facilitates novel speech sound learning.
• To determine if general perceptual abilities, independent of bilingualism, play a role in this learning process.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to observe neural mechanisms in monolinguals, bilinguals, and individuals with advanced (ALs) or non-advanced (non-ALs) learning abilities.
• Participants underwent phonetic training with novel speech sounds embedded in pseudowords over four sessions.
• Behavioral analysis and fMRI data were collected before and after training to assess learning and neural changes.

Main Results:

• Behaviorally, bilinguals did not significantly differ from monolinguals in learning novel sounds.
• Individuals with advanced learning abilities (ALs) demonstrated superior pseudoword discrimination compared to non-ALs, irrespective of language group.
• fMRI revealed increased bilateral superior temporal gyrus (STG) activity in ALs post-training, and bilinguals showed greater STG activity than monolinguals.

Conclusions:

• Individual learning ability, specifically advanced capacity for novel speech sound contrasts, is a more significant factor in speech sound learning than bilingualism.
• Neural plasticity in the superior temporal gyrus is associated with advanced speech sound learning.
• General perceptual learning abilities appear to be the primary driver for acquiring novel speech sounds.