If in voice packages you can't get what you need (Portuguese), then yes, you have to choose something else.
Really stupid, because when I was in Finland this summer, we needed the GPS. My father-in-law is a Finn and doesn't speak French. My 535 (W10M) was only able to navigate in French, not in Finnish! Fortunately, Drive+ was working (and still is on my Lumias), so I downloaded the Finnish package and we used HERE.
You can upvote the many suggestion in feedback app asking to add the voice selection as an option.