We don’t know any Thai swear words, or words for intimate parts of the body, as the lifestyle we lead here doesn’t require us ever having to use them. I’ve consciously learnt how to say don’t poison the grass with chemicals, cut a tiny bit off my hair (because it grows so slowly!), don’t put any meat in my food, and feed the dogs’.
I’d be intrigued to know the Thai phrases that just roll off your tongue because of a need to know/say basis.
VS
P.S. Forgot to add the most important phrase: 'I don't want any ice in my beer!'.
Pete 
I blame it on spending the first 10 down south where the dialect is different but the basics are similar so no excuse. The essentials are no problem for food, drink, getting around, being polite, asking for things. I found myself improving since being in Hua Hin as less of the population speak English. I sit with the Mayors grandchildren most evenings whilst they are doing homework which is proving to help me pick up a lot of irrelevant words and phrases but by the time they are teenagers I should be pretty fluent at this rate. Just hope I do not develop that international schoolkid accent which is like a cross between "valley girl" and Hugh Grant 
Asking what things are on a regular basis helps. "arai na cup?" The rude stuff I learned over years of working with the boat crews so I know some stuff that you would not dare say to the missus unless you were close to an open door and the car engine was running. 