Japanese language Lesson

Pro Language (prolanguage.co.th/) offer Japanese lessons in Bangkok and other cities in Thailand. I've not used this school myself but have read some of their textbooks for Japanese people learning Thai - looks professional and comprehensive (I just read the Thai parts - I've very little knowledge of the Japanese language). I'm sure there are other schools and the Japanese Embassy may be able to make recommendations too.

As for the level, this refers to the Japanese Language Proficiency Test:

en.wikipedia.org/wiki/Japanese_Language_Proficiency_Test

Level 1 is the highest proficiency, level 5 is the lowest, and the above link shows an estimate of 1400-2000 hours study for a level 2 exam pass which seems similar to a high-level pass for the equivalent Thai language competency exam.

BTW, most countries base their language exams on the English TOIEC system, although the number of levels varies (eg. Japanese has 5, Thai has 6 etc).

Best wishes,
Mark