Total Posts: 653
Buenos Aires, Argentina
You need to download you language pack.
After that, you don’’ have to replace the /app/locale/en_US files.
Copy your folder (I think that it’s called pt_PT) in the same folder. Now you have to folders into /app/locale/
If you want to use one or another, change it from the backend. System -> Confgiruation.
Select the general option (it’s the default one). Now you can choose your language.
And the most improtant, go to System -> Cache managment, and clean your Magento Cache.