OE period. Under the influence of succeeding and preceeding consonants some Early OE monophthongs developed into diphthongs. The glide (if a front vowel stood before a velar (задненёбный) consonant), together with the original monophtong formed a dipthong. The front vowels [i], [e] and the newly developed [], changed into dipthongs with a back glide when they stood before [h], before long (double) [ll] or [l] plus another consonant. The changes is known as breaking or fracture. Breaking produced a new set of vowels in OE – the short dipthongs [ea] and [eo]. Diphthongisation of vowels could also be caused b preceding consonants: a glide arose after a palatal consonants as a sort of transition to the succeeding vowel. After the palatal [k’], [sk’] and [j] short and long [e] and [] turned into diphthongs with a more front close vowel as their first element. This process known as diphthongization after palatal consonants. ME period. One of the most important sound changes of the EaME was the loss of OE dipthongs and the growth of new dipthongs, with new qualitative and quantative distinctions. The vowel system lost two sets of diphogs, long and short. In Ea ME the sounds [j] and [] between and after vowels changed into [i] and [u] and formed diphthongs together with preceding vowels. These changes gave rise to two sets of diphthongs:with i-glide and u-glide. e+j= ei, e:+j=ei, +j=ai, a+ =au, o+ =ou, a:+w=ou, a:+x=au+x. NE period. The Great Vowel Shift: during this period all the long vowels became closer or were dipthongised.i: – ai (time) pr ME, a: – ei (maken), o: – ou (stone) – preserved from ME, u: – au (mous – mouse), but au – o: (cause). In Ea NE [r] was vocalized when it stood after vowels, either finally or followed by another consonant. It reduced to neutral sound, which was added to the preceding vowel as a glide thus forming diphthong. Formed э – glide diphthongs – iэ beer (бэр), eэ (there – зэрэ), uэ (moor o-+).
