"What nourishes me also destroys me" is an English equivalent of the French phrase Ce qui me nourrit aussi me détruit.
Specifically, the demonstrative/indefinite pronoun celiterally means "that." The demonstrative/indefinite pronoun qui literally means "who." The two pronouns together mean "that, what, which."
The personal pronoun me means "me." The verb nourrit means "(he/she/it) does nourish, is nourishing, nourishes." The adverb aussi means "also, too." The verb détruit means "(he/she/it) destroys, does destroy, is destroying."
The pronunciation will be "skee muh noo-ree oh-see muh dey-twee" in French.