I took a semester of Thai when I was in college to prepare me for studying abroad. I was averaging a 3.8 GPA at the time so I thought it would be another class I could put on cruise control. I was wrong. Instead, it was the worst academic experience of my life. The class was credit/no credit and I wouldn’t even get a credit.
The problem I had was that I was memorizing useless transliterations – like Pinyin for Thai – to pass the quizzes. This was fine for the first couple of weeks but then it suddenly became apparent: I wasn’t learning anything valuable. Nobody in Thailand could read what I was writing; I couldn’t even read what I was writing. By the time I figured out that I had to use brute memorization to learn their alphabet – actually an abugida – to get anywhere, it was already too late. I had fallen too far behind.
The experience itself was invaluable – even though ego took a beating – and I did learn an important lesson: Learn the native script.
BTW: Thai shares some vocabulary with Mandarin.