The perceptual distance between vowels : the effects of prototypicality and extremity
The present dissertation is concerned with a question of how the perceptual distance between vowels in foreign languages (L2) and those in one's first language (L1) is determined. According to current models of L2 acquisition, the degree of difficulty that the learner faces in perceptually learning L2 sounds is determined by their perceived similarity to the L1 sounds. For instance, Flege's (1995) Speech Learning Model predicts that the learner would fail to establish a separate category for those L2 sounds which are similar to L1 sounds. Although empirical studies support a correlation between perceptual similarity between L1 and L2 sounds and the difficulty of perceptually acquiring L2 sounds, a measure for such similarity is yet to be established. In the first part of the dissertation I investigate possible locations of vowel prototypes, which current models of L2 phonetics see as reference points in determining the perceptual distance between L1 and L2 vowels. As far as vowels are concerned, evidence suggests that unlike visual prototypes vowel prototypes may be at a more extreme location than the centre of the geometrically represented category distribution (Bradlow, 1993; Johnson et al., 1993; Iverson
Nakai, Satsuki
The perceptual distance between vowels : the effects of prototypicality and extremity. The present dissertation is concerned with a question of how the perceptual distance between vowels in foreign languages (L2) and those in one's first language (L1) is determined. According to current models of L2 acquisition, the degree of difficulty that the learner faces in perceptually learning L2 sounds is determined by their perceived similarity to the L1 sounds. For instance, Flege's (1995) Speech Learning Model predicts that the learner would fail to establish a separate category for those L2 sounds which are similar to L1 sounds. Although empirical studies support a correlation between perceptual similarity between L1 and L2 sounds and the difficulty of perceptually acquiring L2 sounds, a measure for such similarity is yet to be established. In the first part of the dissertation I investigate possible locations of vowel prototypes, which current models of L2 phonetics see as reference points in determining the perceptual distance between L1 and L2 vowels. As far as vowels are concerned, evidence suggests that unlike visual prototypes vowel prototypes may be at a more extreme location than the centre of the geometrically represented category distribution (Bradlow, 1993; Johnson et al., 1993; Iverson
perceptual distance vowel effect present concerned question perceptual distance vowel foreign_language first_language determine according current_model acquisition degree difficulty learner face perceptually learning sound determine perceived similarity sound instance speech learning model predict learner would fail establish separate category sound similar sound although empirical_study support correlation perceptual similarity sound difficulty perceptually acquire sound measure similarity yet establish first_part investigate possible location vowel prototype current_model phonetics see reference_point determine perceptual distance vowel far vowel concern evidence suggests unlike visual prototype vowel prototype may extreme location centre represent category distribution johnson