The subject of history of English

1)Diphthongization after palatal consonants(palatalization)

Diphthongs may have resulted from another process in Old English - diphthongization after palatal consonants sk’, k’ and j (in spelling c, sc, ʒ ):

a > ea skal - sceal (shall), scamu - sceamu (shame)

ā > ēa skaggwon - scēawian (to show)

e > ie ʒefan - ʒiefan (give) ʒetan - ʒietan (get)

æ > ea (the æ sound was actually derived from a) ʒæst - ʒeat (gate)

ǣ > ēa (the ǣ sound was actually derived from ā ) jar - ʒēar (year)

o > eo scort - sceort (short) yong - ʒeonʒ (young)

However, there are linguists who still doubt whether the i sound (that is the resulting sound, it was actually a diphthong) was pronounced. Some stick to the opinion that the letter i simply signified the palatal nature of the preceding sound.

The words beginning with ʒ, sc and c with non-palatalized vowel represent dialects other that West-Saxon (ʒunʒ, ʒefan) etc.