Diphthong:

Diphthong,  in phonetics, a gliding vowel in the articulation of which there is a continuous transition from one position to another. Diphthongs are to be contrasted in this respect with so-called pure vowels—i.e., unchanging, or steady state, vowels. Though they are single speech sounds, diphthongs are usually represented, in a phonetic transcription of speech, by means of a pair of characters indicating the initial and final configurations of the vocal tract. Many of the vowel sounds in most dialects of English are diphthongs: e.g., the vowels of “out” and “ice,” represented as [au] and [ai], respectively.

TRIPHTHONGS:

• A triphthong is a glide from one vowel to another and the to a third, all produced rapidly and without interruption. For example, a careful pronunciation of the word ‘hour’ begins with a vowel quality similar to ‘ɑ:’, goes on to ‘ʊ’ then ends in ‘ə’.

• It says /aʊə/

• Triphthong : 5 closing diphthongs with ‘ə’ added on the end.

- eɪ + ə = eɪə . as in layer, player

- aɪ + ə = aɪə. as in lire, fire

- ɔɪ + ə = ɔɪə, as in loyal, royal

- əʊ + ə = əuə, as in lower, mower

- aʊ + ə = auə, as in power, hour.