It's impossible to dynamically change language. But if you just want to change the language of some components, such as textarea, etc., popup window may help you.
Here is a simple sample. I add two buttons on the top of the tour, English and Chinese. You can change the language of scene description and hint of navigation buttons by these two buttons:
here is one example I'm working with.
when the tour starts you can press -> info
then the pop up opens, info is in estonian but if u click ->eng
you will get english info - I used popups and textarea