Apple app Keywords and primary language for a multilanguage app

Hi Guys,

I am a brazilian corona indie developer finally finishing my first app.

It is a really  simple education multilanguage app for children (portuguese / english).

My questions are about the apple publishing process: 

1- What is the best choice for my primary language? 

2 -Should I mix my app keywords in both languages?

I really appreciate any advice!

Thanks a lot!

William.