Epenthesis is when a language adds an extra sound somewhere to make it easier or smoother to say or to make it allowed in the language’s phonotactics (rules about how sounds can be arranged).
In English, to make the plural, you add an “-s” to the end. But for the plural of kiss, kiss-s would not be possible in English, so a small ‘uh’ sound is added between “kiss” and “s”, to make “kisses”.
