Choosing the sample set
We decided that one sample for each of the English vowels on the IPA chart would be a fairly thoroughrepresentative sample of each individual’s accent. With the inclusion of the two diphthongs that we also extracted, we took 14vowel samples per person. We used the following paragraph in each recording; there are at least 4 instances of each vowel soundlocated throughout it.
Phonetic background
(Please i, call a, Ste-ε, -lla ə, Ask æ, spoons u , five ai, brother ə^, Bob α, Big I, toy oi, frog ν, go o,station e)The vowels in bold are the ones we decided to extract; we determined that these would provide the cleanestformants for the whole paragraph. For example, the ‘oo’ in ‘spoons’ was chosen due to the ‘p’ that precedes the vowel. The ‘p’ soundcreates a stop of air, almost like a vocal ‘clear’. A ‘t’ will also do this, which explains our choice of the ‘a’ in ‘station’.
Spoons
The two diphthongs present are the ‘ai’ from ‘five’ and ‘oi’ from ‘toy’. In these samples, the formant valuesmove smoothly from the first vowel representation to the second.
The vowel samples that we cut out of the main paragraph ended up being about 0.04 seconds each with diphthongsbeing much longer to capture the entire sample transition.