All READMEs in English, all code in Portuguese? Really?
Develop an application for support of financial and tax regulations for a certain country. You will have verbs and nouns which describe the situation clearly.
You develop an application from specifications written another language than English. They exist.
The biggest failure I keep seeing are futile attempts to translate concepts under these circumstances into English.
I agree in this case: when you want to invite collaboration on github, English (or Chinese?) would be better suited.
But for Open Source projects coding in English is probably the best way to attract contributors.
Will update here later with an English fork.