For some of us this will involve a mirror.
A languet is (and I quote my Collins Dictionary) anything resembling a tongue in shape or function.
Well, that presumably includes a tongue, then. Can you see your tongue without using a mirror?
Going back to that definition, I find the function bit jolly intriguing. What on earth performs the function of a tongue except, well, a tongue?
A chap stick, which does sort of act as a lip-moistening device?
A spoon? (Well, it saves you having to lap up your soup, or your porridge.)
No, I can't say I'm really convinced by any of these, but the word languet has existed in English since the 1400s, so someone must have found a use for it at some point.
If we can't find something that resembles a tongue in function, what about in form?
photo of a Komodo Dragon by Mark Dumont
I suppose there are ferns;
photo of a hart's tongue fern by Rosser1954
and then there are the things behind the laces on shoes and boots:
photo by Francis Flinch
...but the trouble is that you don't need a special word for those because they're all just called tongues.
Hmm...I may have found a truly useless word, here.
It's really rather sad.
Spot the Frippet: languet. (You say it lang-gwet). This word comes from the Old French languette, a diminutive of langue, tongue.