I’ll be the lone dissenting voice. My dd did not get much from Concordia. Almost all the kids spent their time speaking English. She tried hard to speak only in French, but that was most successful when speaking with the counselors. She got a lot more out of BYU’s French camp. She and her roommate tried to speak in French all day long in addition to the classroom portion…
BYU is more school-like (and I think it offers high school credit) whereas at Concordia she just went for 2 weeks and it was more like camp. BYU is cheaper.