www programming

Do you see any chance that the WP Translater, translates the phpbb forum as well?

For WP I’m working with GTranslate which works quite well.

I know phpbb has some translation plugins available as well but for the user comfort it would be much easier if the WP plugin translate everything.

Hello! Well, no i do not think it can be possible, if not with hard modifications (i could imagine how it could happen, but i also imagine it would be very slow and not efficient under many aspects).
Since this integration plugin ONLY detect email or profile URL or password changes, and manage changes, updating sessions and things for the same user with same email, it cannot interfere effectively with one or the other, which remains two separated CMS. The template integration, again, just display phpBB as an iframe, you can see it like it is a separate site that display into a separate window (within same wp window page)

While if you speak about last topics shortcodes/widgets that maybe display some post's words and you would see these translated, we can imagine that the plugin you use provide a function which cloud be passed to it, the value of widgets posts, so to translate them ($value->post_text) before to display it, into the file
/views/phpbb_last_topics.php
? should be checked but it worth to mention that maybe so, would be better to have a phpBB extension that do the same into phpBB, and that maybe you could hook to the one in wp, so that will display ever the same kind of translation you'll choose into phpBB or wp for the same user.

These are my first thoughts about this.