Other mistake: At the end of the episode, the clock Poirot presents to Miss Lemon is pointed exactly at 3:28, which would be the time of the murder in the original novel, not in this adaption, when it was changed to 12:28.
Other mistake: This adaptation opens with a nice fake Pathe Gazette news reel. The voice says that "last year" Farley sold a record 5 million pies, and that the new wing of the plant is due to open. At the inauguration, there's a banner behind him saying "1885-1935" and he's saying that in 1935 they sold more pies than at any point in their history, and he gives the kind of speech you give at the beginning of a year, trying to set a new record while still on the hot trail of the previous. At the same time, Miss Lemon tells Hastings that the typewriter broke 'last Easter' and she burst out with Poirot that she has been complaining 'for the last six months', which would put the event at the end of the year.
Answer: He definitely says "Belgian", but the subtitles get it wrong and show him saying "American."
Wblank71