Audio problem: In an empty golf course, at such a close distance as shown, there's no way Miss Plenderlieth would not hear Hastings calling Poirot, who "lost another ball." (00:41:20)
Audio problem: When Hastings is caught off guard by the premature launch of the clay pigeon, he fires a couple of shots in a haste. Fairly obvious that he does not, and the mere sound of it has been added in postproduction. (00:01:40)
Answer: He definitely says "Belgian", but the subtitles get it wrong and show him saying "American."
Wblank71