Phonetic Subdivision of Strong Forms of Function Words in English

This paper investigates whether there is a two-way or three-way distinction in the phonetic realization of a function word. Specifically, it is investigated how the English function words 'for', 'in', and 'to' are phonetically realized differently as a function of position in a phrase and phrasal accent. Previous studies (Gimson 1989, Selkirk 1972, 1984, 1996) showed that function words are realized in two forms, strong and weak forms, depending on their context. In strong forms of function words, however, two sub-conditions are mixed: strong forms caused by position in a phrase and strong forms caused by prominence through phrasal accent. Although both the factors play an important role in phonetic realization of function words, the degree of phonetic manifestations in function words could be different depending on the strength of each factor. This experimental study compared five acoustic measurements of duration, F1, F2, intensity, and F0 for the three conditions of each function word: unaccented phrase-medial weak condition, unaccented phrase-final strong condition, and accented phrase-medial strong condition. The results showed that both factors (position in a phrase and phrasal accent) have an influence on the phonetic realization of function words and that the effect of phrasal accent is stronger than that of position in a phrase. To put it another way, it was revealed that a three-way distinction within a function word exists in terms of duration, F2, and F0 measurements: unaccented phrase-medial vs. unaccented phrase-final vs. accented phrase-medial function words.