Thai Language Text to Speech/Selections

I am working on translating a course from English to Thai. I want the course to have a selection at the beginning where the learner can select English, Thai, Spanish, or Japanese for the course material. After the selection I will branch the course off into different scenes. The issue I'm having is: 

1. How can I get the audio for text to speech with Thai
2. If I have them select the language and then branch it out is there a way to change the accessability buttons to the different language too? Example: The Resources button is in English but if they click Thai and then it goes to the Thai scene will I be able to change the Resources button to say Resources but in Thai?