We address methodological issues in calculating the size of the working vowel space area. Although corner vowels are most commonly used in determining its size, we show that this approach may severely underestimate the actual working space. The vowel spaces determined using the large vowels set provided insight into subtle differences between dialects and among age groups. Three approaches were tested which were based on the number of vowels used, formant measurement location and the way boundary lines were drawn.
Index Terms. vowel, vowel space, formants, dialect