You can install multiple Rosetta languages.
After installing, restart your computer and when you launch Rosetta you should be prompted with multiple language selections.
Dear Pete, A big thankyou from me to you! I did what you said and followed your indications and, indeed, I did achieve my objectives by installing Rosetta Portuguese-Brazil. After that I was able to start with my first lesson, Lesson One. The rest will follow when I get there. So, I now have that I was seeking.
Thank you for your professional assistance. I shall count myself most fortunate to have your help again should I need it.
All the best for now,