The french derivational suffix -ment as in 'doucement' ('gently', 'softly') was originally a noun in latin that meant 'mind' as in dulce mente (with a sweet mind). what semantic change has this morpheme undergone?

Metaphorical Semantic Change  is undergone by morpheme.

Explanation:

Semantic change can be known as the meaning of a word that has change over the course of time. It happens when another native speaker adopts English. Metaphor plays vital role in semantic change and it also extant the meaning of proper word and share similar semantic connection between the actual meaning and the new meaning.

The French derivational ‘Suffix- ment’ which means softly and gently is actually derived from the Latin noun mente. which means ‘mind’. for eg. Dulce mente where the word means with a sweet mind.