This study will examine how American listeners perceive differences in duration of vowels (e.g., kiro vs. kiiro) and consonants (e.g., kite vs. kitte) in Japanese words using brain and behavioral measures. Specifically, the study will examine how well American English speakers, with no previous exposure to Japanese, can distinguish differences in vowel and consonant lengthening in Japanese. American English and Japanese speakers are likely to focus on different speech sound properties to recognize Japanese words because, unlike English, Japanese relies heavily on sound duration to distinguish meaning at the word level. This study will examine the question from a novel direction by considering the implications of first-language (L1) perception as an "over-learned" process. The notion of "highly over-learned processes" interfering with second-language (L2) speech perception relates to the claim that in first language learning, infants learn to automatically focus attention on important properties of speech sounds needed for word recognition (Jusczyk, 1997). The brain electrical measure, Mismatch Negativity (MMN), will be used to compare pre-attentive, automatic discrimination of the target sounds to discrimination with focused attention in the two groups of listeners. Research indicates that MMN serves as an index of pre-attentive, automatic discrimination. Subjects whose L1 is American English may not be able to discriminate between words with short and long sounds in Japanese without careful attention. In contrast, subjects whose L1 is Japanese will discriminate between these words without attention as shown by MMN. Behavioral discrimination of the words (pressing a button to a sound change) will provide further information regarding the relationship between preattentive brain responses and behavioral discrimination, which requires attention.
The project will provide insight into how participants discriminate sounds automatically, as indexed by brain measures. In addition, information concerning the relationship between brain responses and overt behavioral responses will reveal how underlying brain processes contribute to the behavioral response and provide insight into the intricacies of the Japanese sound system. The broader impact of this research include several areas. First, the project will allow for development of evidence-based methods of foreign language education that can lead to more native-like speech perception and production. Second, it will contribute to the bilingual education field (infants through adults) and help determine critical periods in which speech perception skills in L2 should be introduced. Third, because it will improve the current approach to foreign language instruction, it will benefit society by improving the communication abilities of L2 learners.
