Other mistake: Poirot, Hastings and The Veiled Lady go upstairs because the lobby is 'too public'. The man spying on them is hiding behind the same newspaper prop used in the previous episode of the season, where Hastings was reading it in Cornwall at the beginning. So must be a pretty old issue now (Peril at End House takes a few days, and they were on holiday). (00:07:40)
Other mistake: The closing credits on the DVD are for another episode, "The Kidnapped Prime Minister." (00:47:15)
Answer: He definitely says "Belgian", but the subtitles get it wrong and show him saying "American."
Wblank71