language lesson vs lesson

language lesson and lesson both are nouns.

Word	Noun	Adjective	Verb	Adverb
language lesson	Yes	No	No	No
lesson	Yes	No	No	No

As nouns, lesson is a hypernym of language lesson; that is, lesson is a word with a broader meaning than language lesson:

language lesson (noun)	lesson (noun)
a period of instruction learning a language	a task assigned for individual study
	a unit of instruction
	punishment intended as a warning to others
	the significance of a story or event