Revealing mistake: The phone book has a LMS logo on the page edges in the close-up where we see Poirot actually flip through - the logo disappears when he is moving the book in the rest of the scene. (00:16:10)
Revealing mistake: The stuntman smashing through the window is quite obvious - he does not even have the hair styled like Hastings'. (00:31:30)
Answer: He definitely says "Belgian", but the subtitles get it wrong and show him saying "American."
Wblank71