Vowel the vowel sounds of "flower", , form a triphthong or disyllable, depending on dialect. In phonology, diphthongs and triphthongs are distinguished from sequences of monophthongs by whether the vowel sound may be analyzed into different phonemes or not. For example, the vowel sounds in a two-syllable pronunciation of the word "flower" () phonetically form a disyllabic triphthong, but are phonologically a sequence of a diphthong (represented by the letters ) and a monophthong (represented by the letters ). Some linguists use the terms "diphthong" and "triphthong" only in this phonemic sense. The name "vowel" is often used for the symbols
Phonological history of English diphthongs case uncertain). Typical diphthongs are considered to have been as follows: As with monophthongs, the length of the diphthongs was not indicated in spelling, but in modern editions of OE texts the long forms are often written with a macron: , , , . In the transition from Old to Middle English, all of these diphthongs generally merged with monophthongs. Although the Old English diphthongs merged into monophthongs, Middle English began to develop a new set of diphthongs, in which the second element was a high or . Many of these came about through vocalization of the palatal approximant or