Same same but different: The graded influence of vowel quality and prosodic prominence on letter detection

This study investigates the impact of phonetic realisation and prosodic prominence on visual letter identification, focusing on the letter <e> in German bisyllabic words. Building upon previous research, a computerised letter search task was conducted with 78 skilled adult readers. Words featuring different phonetic realisations of <e > (/eː, ɛ, e, l̩, n̩, ɐ/) in stressed and unstressed first and second syllables were systematically included. Analyses of error rates and response times revealed a graded pattern in the detection of <e>, with the closed long (/eː/) and closed short (/e/) realisations being easiest to detect, open (/ɛ/) and near-open central (/ɐ/) vowels becoming incrementally harder, and silent vowels in syllabic consonants (/n̩/) being the most challenging. Results divided by position and stress of the syllable containing the target letter further indicated influences of prosodic prominence. The findings contribute to understanding the intricate interplay of grapheme-phoneme correspondences and prosodic structure in skilled readers' visual letter recognition.