internal sandhi
Definition - A type of sandhi in which changes occur at the morpheme boundaries within words.

For example, in English, the plural suffix -s is pronounced as /s/ after voiceless consonants (e.g. cats) and as a /z/ after voiced consonants (e.g. dogs).

As opposed to external sandhi where changes occur at word boundaries, e.g. in English when we use an if the following word begins with a vowel and a if it does not.

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