This is extremely impressive! Congrats on this accomplishment. You say that you don’t have a lot of ECs but I imagine you must have spent a lot of time outside of school building your fluency in languages. If so, even if it was self-study, you can definitely let colleges know about your passion for languages and the amount of time you have devoted this passion and count it as an EC. This really sets you apart from other applicants and will make you stand out in the admissions process. Keep this in mind when crafting your essays.
Are these really your interests or are you trying to pick something typical and standard? You did a summer camp in Linguistics, you are fluent in six languages, you volunteered at a library, you say writing is your strong suit and you enjoy foreign travel… you are amazing!!! Why not list your intended majors as Linguistics and International Studies? You would be building a really unique, interesting, and cohesive profile. Of course, if you’re passionate about Econ, that’s fine. But I don’t really see a passion for Econ jumping out. Your profile is pointing to something far more unique. Lean into your passions and let your college applications reflect that.