Overview

The study aims to compare vowel reduction in read and fully spontaneous speech in English and Polish. It hypothesises that (1) vowels exhibit stronger reduction in fully spontaneous speech in comparison with read speech in the two languages, (2) vowel reduction is more robust in English than it is in Polish, and (3) a high speech rate triggers vowel reduction. The aims were achieved by an acoustic analysis of interviews and wordlists from PAC (nine speakers) and the Corpus of Modern Spoken Polish in the area of Greater Poland (nine speakers). The study treats centralisation of formants and reduced vowel duration as vowel reduction (Lindblom 1963), which were normalised to compare the values across speakers. For Polish subjects, speakers’ canonical schwa was operationalised as an average of peripheral vowels /i/, /a/ and /u/ due to the fact that Polish has no schwa (Jassem 2003). The comparison of two speech styles consisted in measuring spectral and temporal properties of vowel tokens from the wordlist and from the interviews. The rate-reduction hypothesis was tested by means of comparing vowel reduction for the three fastest and the three slowest speakers for each language and using Pearson correlation.

In light of the obtained results, the first two hypotheses were positively verified. The third one produced negative results. The study establishes a significant difference in vowel reduction across two speech styles – read and fully spontaneous – across two unrelated languages. It has been demonstrated that reduction in English is considerably stronger than in Polish. More specifically, in both languages duration followed the same pattern (towards shortening in spontaneous speech relative to read speech), whereas for formants, centralisation was established for English, but not for all Polish vowels. With respect to the third hypothesis, assuming a straightforward relationship between speech rate and reduction, the findings of the current study did not lend support to either language. As Zwicky notes, ‘casual speech need not to be fast; some speakers […] use a quite informal speech even at fairly slow rates of speech, while others […] give the impression of great precision even in hurried speech’ (Zwicky 1972: 607).