It's quite a temple where the portuguese here spoken is carved on the walls and whispered all the way trough the museum. It really shows how the language is alive and, in Brazil, it mixed with so many other cultures it turned out to be a very different new language.
So, if you go there, you will have this kind of experience, so don't even expect to see the things in English (it would be like going into a Vatican church and see Bible passages writen in arab, or otherwise).
As my girlfriend is from the northeastern part of Brazil and I'm from São Paulo, there are some regional difference in the language and the museum explored it so well it was just amazing!
It would be a flaw to forget to say about the seasonal expositions, where the life and work of a specific writer or poet is shown. I went at the Fernando Pessoa exposition and it was wonderful! I believe these last months this place is under repairs...
And yes, it's a 3 hours max trip and I suggest to go by Metrô (subway) to take a look inside Luz station and, after the MLP to go visit the Pinacoteca, eating a nice pasta at its café.
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