GPlugin has finally been added to the Pidgin organization on Transifex. Previously it was in a Guifications organization that I didn’t realize was private until today.
We also added Ibis to the Pidgin organization on Transifex as well. Ibis is our new IRCv3 library that is being developed and used in purple3.
There’s no rush in getting translations in on either of these as any releases are just for development right now, but if you want to do it anyways, we won’t stop you! 
Is Pidgin Transifex still accept new Languages or nah?
We’re trying, but not much has changed string wise in pidgin 2 forever, so translations have been basically left as is for awhile now.
Also there are a ton of things to do and with Pidgin 3 being far from usable for end users there’s not much to gain right now by taking on the maintenance burden of translations.
Then I just suggest an Idea of Feature:
Be able to change Pidgin’s Language via Settings/Preference in Interface/Appearance Section.
That’s not possible with gettext as far as I know. It has to be set at startup and to my knowledge there’s no way to change it aside from restarting so preferences wouldn’t work.
Restarting is OK, just I think that it would be nice-to-have Feature.
sure, but it’s built into the operating system in most cases. On a unix like environment you just launch it with the LANG environment variable set to the proper language and it’ll use that language. But again, that’s not something we can really do in the application as the translation stuf needs to be setup way before the preference stuff so it’s just not feasible.