affirmation vs speech act

affirmation and speech act both are nouns.

Word	Noun	Adjective	Verb	Adverb
affirmation	Yes	No	No	No
speech act	Yes	No	No	No

As nouns, speech act is a hypernym of affirmation; that is, speech act is a word with a broader meaning than affirmation:

affirmation (noun)	speech act (noun)
a judgment by a higher court that the judgment of a lower court was correct and should stand	the use of language to perform some act
a statement asserting the existence or the truth of something
(religion) a solemn declaration that serves the same purpose as an oath (if an oath is objectionable to the person on religious or ethical grounds)
the act of affirming or asserting or stating something