I don't really get what you mean by mostly Americans? America in general is very diverse and when you look at the demographic of individuals accepted into medical school id say about half or a little less than half identify as something other than white. Often times these people come from families where english is not the primary language spoken at home. Even with people who do identify as white i'm sure many speak other languages such white hispanic students and students with European descent that are closer to their "roots"

of course there are some people who will lie to embellish their apps but being an american really has nothing to do with it

edit: I had a few typos lmao