Our hs quickly added Arabic, but the French teacher was fluent and, at the time, there were grants to support this. A trial class was immediately full. Then they hired a part timer.
But what lang is OP so interested in and would it fill a defensible gap (eg, hs with Spanish but no French?) Or this is just what OP wants?
Why can’t it be an outside course online? Why does it have to be for credit? If you study online, there are ways to show colleges your mastery.