When uploading you can upload a preferred language for activists. Use the language's code to set the language for that activist. If not set, default is English, unless you have set another default in your group settings.
Accepted languages and codes are English (en), Danish (da), Dutch (nl), Finnish (fi), French (fr), German (de), Indonesian (id), Japanese (ja), Moldovan (mo), Portuguese (pt-BR), Russian (ru), Spanish (es), Swedish (sv), Turkish (tr), and Welsh (cy).
You can assign activists to countries by uploading a country code. Use the two digit country code to set the country. If not set, default is the US, unless you have set another default in your group settings.