objection vs speech act

objection and speech act both are nouns.

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

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

objection (noun)	speech act (noun)
(law) a procedure whereby a party to a suit says that a particular line of questioning or a particular witness or a piece of evidence or other matter is improper and should not be continued and asks the court to rule on its impropriety or illegality	the use of language to perform some act
the act of protesting; a public (often organized) manifestation of dissent
the speech act of objecting
the act of expressing earnest opposition or protest