twirl vs birl

twirl is a noun but birl is not a noun.

Word	Noun	Adjective	Verb	Adverb
twirl	Yes	No	Yes	No
birl	No	No	Yes	No

As verbs, twirl and birl are synonyms defined as:

Other synonyms of twirl include spin, whirl.

twirl (noun)	birl (noun)
the act of rotating rapidly
a sharp bend in a line produced when a line having a loop is pulled tight

twirl (verb)	birl (verb)
turn in a twisting or spinning motion	cause to spin
cause to spin	cause a floating log to rotate by treading