I struggle with languages. The best thing I did was learn to read and write Thai. It is not so difficult and will pay dividends learning the language in the long run. Also self study is easy this way

Ais has a system called multi sim. both use the data plan and either cad is switchable to become the single phone access card. It works well if you have a phone and a backup as they use the same number. Not an issue if you want a data only connection. For this I use a True sim card in a D link portable router 300 baht a month unlimited data. It is fast enough for all I do dtreaming video included.