Definition from Wiktionary, the free dictionary
to speak to (phrasal verb)
- (idiomatic) To give evidence regarding something; to attest for.
2006, Staff of Vault, The College Buzz Book, page 176:
- This definitely speaks to the fact that at Georgetown, beginning at the admissions process, you're not a number but a real person.
- (idiomatic) To address a particular topic.
1981, McGill journal of education:
- Education for being speaks to what grows within the person himself
- (idiomatic) To (figuratively) resonate with, to feel emotionally relevant to.
- His music really speaks to me.
These usages are in addition to the main (and not idiomatic) usage meaning "to address one's words to (someone)".
to give evidence regarding something