Perceptual features of unknown foreign languages as revealed by multi-dimensional scaling

Adult listeners can discriminate between and can often identify spoken samples of unknown languages. Two studies explored which perceptual properties inherent within the phonological structure of languages are salient to foreign language listeners. In Study 1, 15 subjects were asked to judge whether pairs of spoken foreign language sentences were selected from same or different languages and to explain how they had made the judgement. A multi-dimensional scaling (MDS) was conducted on the subject responses for the same-language condition. The resulting map revealed that responses could be characterized along two dimensions: phonologically-based psychoacoustic properties and talker-specific characteristics. The two dimensions define the distinctiveness of the languages and elicited different perceptual feature relationships in subjects. In Study 2, these perceptual feature relationships were tested using similarity judgements. 30 subjects rated similarity on a 7-point scale for the same set of sentence pairs that had been judged in Study 1. MDS analysis revealed that the different-language condition yielded a map in which the language proximities closely approximated those which had been derived by focusing on phonological properties. This suggests that, since analysis of both different-language and same-language sentence pairs produced similar maps, perceived language similarity among foreign languages depends upon the listeners´ salient organizational categories inherent within the phonological structure of language and the talker-specific characteristics of voice quality and speech rate