"Useless to try to escape; it's locked."
Translation:Inutile d'essayer de t'échapper, c'est fermé à clé.
Has the distinction between teaching the written and the spoken word been lost? Teaching has required a higher standard of grammar for the written word. While the boundary may have become blurred, is it not incumbent upon a teacher, using the medium of the written word, to hold to this standard? Duo has apparently abrogated this responsibility and it should make it clear to its students that it is teaching colloquial, americanised english.
Three corrections. First, DL is teaching French here, not English, and in particular is teaching constructions that make sense in French but are awkward (at best) in English, so a certain amount of leeway with English is called for. Second, 90% of DL's (frequent!) English mistakes have nothing to do with being either colloquial or American. Owlish (the language that Duo seems to speak) bears very little resemblance to actual colloquial American English! Third, concerning the remaining 10%, there's no such thing as "americanised English". American English is not a corruption of British English, just as British English isn't a corruption of American English. They're just two branches of the same tree that diverged 250 years ago, both of which differ greatly from their early modern roots. While DL tries to support both dialects, DL is an American company whose market is more American than British, so naturally the default version of English is American.
Bottom line: I share your frustration with the low quality of DL's English translations. This is also a problem with staff-produced content in other languages, particularly the massive recent expansions of the EN => Spanish tree. But Owlish isn't colloquial English or American English. It's just bad English.