The Assibilated Sound in Modern English

Linguists divide these vowels into two groups, the back vowels and the front vowels. The k sound is pronounced in the back of the mouth like the back vowles, a, o and u. But when the k sound came before a front vowel pronounced in the front of the mouth, then the sound tended to shift to the front - making it hissing or hushing. This was true throughout all those languages. In fact, as a general rule, in modern english, when the k sounds appears before an, a,. o or u in any words which were inherited from this period, the word is still spelled with its original c'