Nowadays there are many language schools in Phuket, aimed not only to local Thai people but also to foreigners. Most schools are teaching English but there are also a number of schools that teach Thai and Chinese to foreigners.
Especially for those expats who plan to live or work here in Phuket, learning Thai makes life so much easier to be able to communicate with the locals. Thai people are very friendly and love it when foreigners make an effort to learn their language.
For those foreigners who have TEFL or TESOL qualifications then it is also an opportunity for you to work as a teacher in Phuket.