I'm guessing most farangs know the basic ingredients in transliterated Thai... gai / kai, nur / neur, kao / khao, etc. And you can Google any ingredient name to find it on many websites, even ones with sound files to help you pronounce somewhat correctly. But useful phrases regarding ordering Thai food the way you want, or asking questions in a Thai market... I would love an endless list of them, since I don't speak Thai.

For example, I use peht maak maak (spicy, very very) but I still get varying degrees of spiciness. I'd love a phrase more colloquial, like "enough kee nu chillis to kill your grandmother" - which in a honor driven culture, you'd NEVER say to a stranger, much less someone who's preparing your food. :-) One moldy rat curry, coming up! But something that says, look, make it hotter than you yourself can eat... without sounding rude or implying incompetence.