14 years here and can speak passable Thai, I have manage Thai tradespeople for over 10 years and that has helped.
Just started to learn to read and write, and is does help youunderstand the tones better, but a nightmare to learn when you are over 50.
Was shamed into it by my 6 y.o. daughter.
After about 3 months I can read number plates and short phrases, get a kick out of it actually.
I agree with a few posts here, better to learn using the Thai script then a phonetic (spelling?) one.