Language in school? It's discordant (7)
I believe the answer is:
screech
'it's discordant' is the definition.
(a screech is a discordant sound)
'language in school?' is the wordplay.
'language' becomes 'cree' (Cree is an example).
'in' is an insertion indicator.
'school?' becomes 'sch' (common abbreviation).
'cree' placed within 'sch' is 'SCREECH'.
(Other definitions for screech that I've seen before include "Terrifying sound" , "Sudden shrill cry" , "Yell" , "Raucous sound" , "Sharp piercing cry" .)