ABSTRACT
A diphthong is a single sound produced when two vowels, one dominant in duration and stress and one reduced in duration and stress, are paired together in a sequence. Diphthongs are not included on the IPA charts because they are the result of the pairing two pure vowels. There are five diphthongs commonly used in GAP: /aI/, /aʊ/, /ɔІ/, /eI/, and /oʊ/. In all cases, the first vowel is longer in duration and exhibits more stress. It is important to note that the close combination of the two vowels causes each of the vowels to lose its pure quality. The /I/ in [aI] is quite different from the /I/ in [It]. Diphthongs can be found in both open and closed syllables. In phonological patterns, diphthongs are labeled using a single V symbol because the they act as one sound.
