Do most? No. Do many? Yes. If she is applying to a college that suggests 4 years of a single foreign language (of which Penn is not one), then yes, her application would be less-than-competitive. More info can be found here:
http://talk.collegeconfidential.com/college-admissions/1802227-faq-foreign-language-p1.html
Relatively few. I can’t vouch that the info on the below is 100% accurate since it’s 4 years old, but it gives you a place to start; your daughter can certainly research the requirements for her target schools:
https://www.asdk12.org/cms/lib/AK02207157/Centricity/Domain/1252/University%20Reqs%202014.pdf