long suit vs speciality

long suit and speciality both are nouns.

Word	Noun	Adjective	Verb	Adverb
long suit	Yes	No	No	No
speciality	Yes	No	No	No

As nouns, long suit and speciality are synonyms defined as:

Other synonyms of long suit include forte, metier, specialty, strength, strong point, strong suit.

long suit (noun)	speciality (noun)
an asset of special worth or utility	the special line of work you have adopted as your career
in a hand, the suit having the most cards	a distinguishing trait
	an asset of special worth or utility