I've been able to get by with English here in Chiang Mai with no major issues. But here's some very basic but useful phrases for travelling in Thailand:
- Hello: pronounced like sah-wa-dee-khrap for men and sah-wa-dee-kah for women
- Thank you: kop-khun-khrap for men and kop-khun-kah for women
- Yes: chai-khrap for men and chai-kah for women
- No: mai-chai-khrap for men and mai-chai-kah for women
- Bye: Lah-gohn-khrap for men and lah-gohn-kah for women
I found this YouTube video pretty good with pronunciations and stuff.