dictation vs speech act

dictation and speech act both are nouns.

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

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

dictation (noun)	speech act (noun)
speech intended for reproduction in writing	the use of language to perform some act
an authoritative direction or instruction to do something
matter that has been dictated and transcribed; a dictated passage