Is it possible to change the text on the buttons in the interactive tour? Either by having the same language shown for all users, or making the button text dependent on a user setting?

You can update the default text on the buttons for all guides and all users.

We call this a tiplate (tip + template).

If you want to update the text of the next button on a specific guide for all users you can do that using the setting 'Change Next button text to'. You will find it in the display setting in the Guided Learning editor.

If you want to change the text of the next button on a specific guide based on a certain user setting you can do that too.

First you will need to set an Guided Learning variable like so:

iridize("api.vars.set", {"username":"007"});

than you can set the 'change next button text' setting to:

{{username}}

and the button will then display 007 (instead of next)