atestiguar

v. testify, bear witness; attest; vouch

= witness, bear + witness, speak to.
Ex: We sometimes only have to speak a word to witness a reaction in other people that should logically follow only if the object itself were present.
Ex: Controversy and antagonism attended each area of investigation, as a flood of secondary publication bears witness.
Ex: These reasons speak to the duties and enduring mores of the professoriate.