@fullfathomfive , After one year on Duo and dodging adverts and rubbish I find that it's designed to string you along as long as possible, ie no info on grammar bar what you figure yourself is a major shortcoming to learn a language properly within a shorter amount of time.
I'm glad there are suggestions in the thread for open source language learning, I will definitely check these out.
Thank you for your major effort to help people learn new languages.
It is a huge foundation for peace & love.