If you mean language as in English or French or German, etc., then the answer is not easily.
There are no commands that check for language preference on the device the Tier 1 app is running on.
And there are no commands for switching between languages.
You would need to implement such a system yourself and have the user select the language they want to use.
Having implemented a similar system on a PHP based website, it can be a royal pain.
You need to have a file of indexed text strings for each language you choose to support. Then you would need to read in the desired file into an array and use those values for all displayed text (unless it is in an image). If your displayed text is actually part of images, then you would need a set of images for all supported languages and load the correct images for the target language.
Cheers,
Ancient Lady
AGK Community Tester