Question: What role does being bilingual or trilingual play in admissions? How much of an advantage is it?
Admission officials certainly respect any student who can speak more than a single native language, but, these days, there are so many multilingual students--especially international students--applying to U.S. colleges and universities that multilingualism can often be only a very tiny plus. A lot depends on the specific circumstances. For instance, a student who speaks two languages that are native to his or her own country plus English, learned in school (which, of course, is requisite when applying to American colleges), won't be as impressive at admission-decision time as a student who learned an atypical language, perhaps through independent study or by doing extensive volunteer work with a disadvantaged population or in a foreign country.
In addition, college admission officials are always seeking students from underrepresented nations--in other words, those who don't usually attend their institution. Thus, a student from an uncommon background might get a boost in the admission process, not so much because of the languages he or she speaks but because the candidate hails from a place where those languages are spoken.