A. Language proficiency is just not a big factor in admissions. And AOs don’t want certificates of accomplishments. The applicant certifies that the information is accurate and any inaccuracies discovered will have consequences.
B. Many applicants (wrongly) claim proficiency simply based on passing the AP exam, so many AO’s are just going to skip over that claim. And if the applicant really does have proficiency, see A above.
As an aside, it is my fervent hope that applicants I interview don’t ever tell me they are fluent in a language. Because if it’s a language I know, I’ll briefly speak to them in that language and invariably, unless the language is Spanish, they look at me like a deer in the headlights. 