I found it profoundly difficult to learn and speak, mainly becuse i have about 70-80% hearing loss in both ears thanks to my service days.
I am proficient now, but unless Thai's know my accent they cannot understand me well - my tonal speech is crap.
My daughter shamed me into learning to read and write, I went really well and it was a lot easier to pick up once i put my head down. But like all things i lost my motivation once i could read most of the alphabet and write my name, there seemed little challenge left.
My wife was absolutley no help whatsoever, she has no patience with a near deaf student.
My daughter is a gem, we converse more than my wife and I do in Thai.

It is compulsory to be able to speak it to get your Residency Book, and I managed that OK, plus a basic written test. The only ambition would be to go for citizenship, but that would be like getting a diploma in being stupid, pigheaded and just plain lazy.

Don't see the point in that!