The purpose of the present study is to increase the naturalness of the rule synthesis developed at the Department, especially positional variants of phonemes. We have in this study chosen the Swedish short vowel /e/, as this vowel is highly variable and can show a great degree of reduction. A statistical analysis of the second formant value as a function of the phoneme context (CVC) gave as result that the variability expressed as standard deviation was reduced by 38% on the training material and 24% on the test material. Analysis of the spectra of /e/ vowels showed that there was a tendency of acoustically different allophones to appear, that is, different spectral envelopes, due to context and position.

Keywords: analysis, synthesis, reduction, vowels