My high school does not offer the foreign language I wish to study...?

Talk to more people about being allowed to take the cl. If the rules say that you are allowed to do so then your school should help you, you just need to find the right people to ask and your guidance councelor obviously isn't one of them. Can your parents help you or a teacher or the headmaster? They shouldn't be allowed to hinder your learning. Try a few more options before you decide to try the internet. You should be able to take that cl.