Okay, I concede that I may have forgotten that Chinese has its exceptions too. 了解 is indeed a good example. There are plenty in English though. Even with context, sometimes I have to really pause and think whether to pronounce read as red or reed (I read it just fine, I read English just fine).

Where I've had pain specifically with Thai is that I can't even know where a syllable begins and ends until I read a few "syllables" together and decide whether some vowels go with the consonant in front or behind it, and whether some an -ar should be pronounced as an -aan.