Formant frequency information for vowels averaged across 4 male speakers.
A data frame with the following columns:
- A factor indicating speaker sex.
- The vowel category in x-sampa.
- A numeric vector indcating the vowel F1 in Hz.
- A numeric vector indcating the vowel F2 in Hz.
Bradlow, A. R. (1995). A comparative acoustic study of English and Spanish vowels. Journal of the Acoustical Society of America 97. 1916-1924.