My son took Spanish 1 in 7th grade, Spanish 2 in 8th grade, Spanish 3 in 9th grade, Spanish 4 in 10th grade and AP Spanish this year. Should he start a new language senior year or take a non language academic elective instead?
He should choose based on interest.
But note that while high school level 5 / AP in Spanish will probably get him a few semesters of advanced placement in Spanish if he chooses to take it in college (based on AP score or college’s own placement exam), high school level 1 in some other language may give him 0-1 (probably 0) semester of advanced placement in that language in college.
Colleges want you to get to level 4 of a language. Your son has finished AP level so he has met any requirements that colleges have.
If he is very interested in Foreign Languages and may major in that area or international relations, then I would say yes.
If he wants to major in STEM or typical humanities then no, just take an elective (academic or not).
He’s met the level colleges want so it can take another language (such as if he wants to go into international relations, global management…)