I've been learning japanese for quite a while and always wondered why :
could be an order. Whereas something like :
can't be an order.
Because basically, 【言ってんじゃねぞ】 is just :
言う の テ形
助動詞 いる not pronounced since it's a contraction
Contraction of the particle の (ん)
So I don't understand why 【○○てんじゃねえぞ】can be understood as :