The impact of orthographic forms on speech production and perception: An artificial vowel-learning study

Abstract

This study investigates the effect of orthographic forms on phonetic aspects of isolated speech sound production and perception. Three groups of 25 L1-Spanish speakers were exposed to /y/ and /ɛ/ in a multi-session learning study. They heard the same vowels presented with: L1-incongruent orthographic forms, novel orthographic forms, or without orthographic forms. After three exposure sessions, participants were tested on vowel production in an elicited production task and vowel perception in a multiple forced choice task. All groups established new /y/ and /ɛ/ production and perception categories. Incongruent orthographic forms led to less target-like category positions for /y/ but not /ɛ/ in production and perception. Novel orthographic forms only facilitated more target-like perception for /y/. In a fourth session, Auditory-only participants were exposed to incongruent orthography for /y/ and novel orthography for /ɛ/. Sequential exposure to incongruent orthography caused less target-like production and perception category positions, while sequential exposure to novel orthography altered neither. Together these results suggest that orthographic forms affect isolated speech sounds and are encoded at the speech sound level. Incongruent grapheme-to-phoneme mappings from L1 to later-learned languages may critically affect the phonetic characteristics of non-native speech sounds, but learning outcomes depend on specific L1-L2 category contrasts.