Nashua, N.H.-based Transparent Language offers a free seven-day trial of its Transparent Language Online products. 

When I say “products,” I really mean plural: during the trial you can try out any and all languages they have, and they have materials for over 100 of them.

I have looked at Irish and German, and I confess I was not blown away by what I saw. But for some of you language nerds out there (and that is a compliment, coming from me!), this might be a good opportunity for you to tool around among dozens of languages at no charge: Pashto, Tagalog, Japanese, Hindi, Luxembourgish, Macedonian, Hungarian, Tuvan, Zulu, and more.

At the very least, multilingual types can refresh waning vocabulary skills in multiple languages using Transparent Language’s online flashcard applications (just go to the Byki Vocabulary section). I think that could be fun!

Please consider the rating here to apply to the free trial and not to the product as a whole. I didn’t spend enough time on it to evaluate it fully. To be honest, I can see it is not my type of learning application, but as with any no-cost access, the only risk to you is your time.