Consonant Mutation in English

Consonant mutation is the change in a consonant of a word due to the morphological or syntactic environment. It is evident not only in English but in languages all around the world. Consonant mutation provides evidence of sound change.

In Old English velar plosives were palatalized in certain environments. This resulted in alternations. This can be seen in the doublet ditch/dike.

Consonant mutation occurs in the past tense of certain verbs. These include seek/sought and think/thought. Consonant mutation also occurs in loanwords from Latin. Compare confess/confession and fuse/fusion.

The palatalization of velar plosives before front vowels results in forms such as induce/induction and produce/production. In act/action the word-final alveolar alveolar plosive of act is replaced with an alveopalatal fricative in action. 

Consonant mutation provides evidence of sound change. In English consonant mutation is often observed in verbs and in loanwords from Latin. Though consonant mutation can occur in all parts of the world, it usually occurs word-finally.