Obviously every school is different, but high school would almost be too late to introduce a new language class in our town. The majority of kids continue on with the language they started in 7th grade, which is when world language classes start here in earnest (though our schools dabble with them in grades younger than that).
Would your HS accept a dual enrollment class in lieu of a language class not offered at your HS? Ours accepts ASL and Japanese through DE as satisfying the HS world language requirements. That seems a less expensive compromise.