A diphthong is a complex vowel that is considered a single sound despite two distinct tongue movements. These movements happen across a narrow enough part of the vowel space with enough speed that they are perceived as part of a single sound. The English word eye is a good example of a diphthongal vowel. The sound consists of two parts: /a/ (as in the first sound in father) followed by an /ɪ/ (as in the vowel in bit). The diphthong in eye is written as [aɪ] or [aj]; though, there are differing views on whether diphthongs are written as vowel-glide sequences or VV pairings.
The diphthongs of English include:
- [aɪ] as in eye,
- [ɪə] as in dear,
- [eɪ] as in care,
- [ɔɪ] as in joy
- [əʊ] as in own, and
- [aʊ] as in town.
For more information on the diphthongs included in the Gaelic phoneme inventory see Sounds of Scottish Gaelic.
- Ladefoged, D. (2010) A Course in Phonetics. 6th Edition. Wadsworth Publishing.