parlance vs formulation

parlance and formulation both are nouns.

Word	Noun	Adjective	Verb	Adverb
parlance	Yes	No	No	No
formulation	Yes	No	No	No

As nouns, formulation is a hypernym of parlance; that is, formulation is a word with a broader meaning than parlance:

parlance: a manner of speaking that is natural to native speakers of a language
formulation: the style of expressing yourself

Other hypernyms of parlance include expression.

parlance (noun)	formulation (noun)
a manner of speaking that is natural to native speakers of a language	inventing or contriving an idea or explanation and formulating it mentally
	the style of expressing yourself
	a substance prepared according to a formula