I think by that logic almost all words in every language predate the language they are part of. Like saying that our noses aren't really human because noses predate humans.
a neglected toddler
What do you mean by this?
As island-based languages go English is probably the least isolated in history. It's Germanic relatives are all nearby. Britain has had extensive links to the continent for the entire history of English and well before. It's an international language and has been for hundreds of years.
English also isn't that weird just because it got a large infusion of (pretty closely related) Norman words after 1066. Korean, Japanese and Vietnamese all have over half their lexical items from Chinese, an unrelated language.