Vowel-to-vowel coarticulation in Spanish non-words: Effects of stress and consonantal context

In spoken language, gestural overlap in speech production regularly leads to coarticulation between neighboring segments, resulting in assimilation measurable by changes in the acoustic parameters. Vowels in adjacent syllables can coarticulate in a phenomenon called vowel-to-vowel coarticulation, which is subject to variation based on environmental factors such as surrounding consonantal context and the placement of stress. This study investigates vowel-to-vowel coarticulation in Spanish in order to better understand the effect of stress and consonantal context on coarticulation. Formant analysis of vowels produced by 20 native speakers of Spanish was used to determine the presence and direction of coarticulation in trisyllabic nonce words with varying stress (/CVCVCV/ words, vowels /e, o/ as targets and /e, i, o, u/ as triggers, /k/ and /p/ contexts). Results showed that both anticipatory and carryover vowel-to-vowel coarticulation was present at vowel edges in all contexts, but only carryover coarticulation in backness extended to vowel midpoints. Stress placement mediated the coarticulatory effect with select target and trigger combinations in carryover coarticulation, while consonantal context played a greater role in anticipatory coarticulation. When stress played a role, unstressed target vowels were more susceptible to coarticulation, while stressed targets resisted coarticulatory effects.