The Hebrew vowel system: raw and normalized acoustic data.

It is well known that different languages use different vowel systems in terms of variety and number. The Hebrew vowel system consists of five vowels /i, e, a, o, u/. The present research identified the acoustic features of the vowels produced by Hebrew speakers differing in age and sex. Ninety speakers (men, women, boys, and girls) were recorded. The vowels were presented in a nonword context that was placed in a meaningful Hebrew sentence. The data included measurements of F0, F1, F2, F3, F4, and vowel duration for the five different vowels produced by the four groups of participants. Conversion of the physical frequency measures of formants into a critical band (bark) scale was performed as well. The results indicated that the F2/F1 ratio is a distinctive feature of all five vowels, keeping with the findings of previous research in other languages. Nevertheless, the values of the F2/F1 ratios led to an overlap between different vowels produced by different groups of speakers. Applying the bark transformation as speaker normalization procedure succeeded in reducing speaker differences while increasing vowel differences.