I've tried right now. The pdf is in English. I've downloaded English voice, but it keeps reading with the Portuguese voice (so, it can't read properly).
Then you also have to be aware that some pdf:s are made in a way that makes it hard to select text in a logical way. The text is presented ok for the eye to read, but unlogical for a machine to read. Maybe some dedicated reading programs are better than macOS in coping with these difficult pdf:s, but the main problem is in the creation of the pdf-file itself.