Table 3. The four classes of vowels based on their estimated effects on probability of perceived prominence as shown in Table 2
Class
Vowel
1
/ɛ/, /ʌ/
2
/ɑ/, /ɔ/, /aʊ/, /i/, /æ/, /oʊ/
3
/eɪ/, /ɪ/, /ɝ/, /u/
4
/aɪ/, /ʊ/, UV
UV, unstressed vowel.