Facilitating a workshop session on using Duolingo in my college
I'm considering proposing to facilitate a session at my college on using Duolingo for our language courses. I'd plan to show other instructors the benefits of it, how to use it, etc.
My first question is whether or not this is technically legal, or approved of? Secondly, if so, how can I "cite" the trademark of Duolingo? With just a (TM) symbol after it, or is there a preferred way?