Can you make GBbooks in different languages?

Potentially yes, but it is not something that should be assumed automatically for every request. Language affects layout, text flow, character handling, visual balance, and sometimes the overall practicality of the adaptation. Some texts translate more cleanly into the format than others, and some language-specific details may need to be considered before production. So the realistic answer is that language customization may be possible, but it is the kind of detail that should be checked case by case rather than treated as a universal default across every title and every request.