...but will probably never get around to.

This is a thread to list the languages you would love to learn but, realistically, you will most likely never learn for whatever reasons.

Russian. It's useful, but a nightmare for the learner.

Hindi would be nice, but I've got too much on my plate right now.

Certain languages like Finnish, Korean and Basque are really fascinating for various reasons but I would never learn them except as a challenge (and I have enough challenging languages as it is).

Cantonese... Taiwanese... and Darija.

As fascinated as I am about Osage, I doubt I'll ever learn it. Materials are simply too hard to get a hold of, not to mention speakers.

If I was ever going to learn Arabic, I think I would've done so by now. I mean, I did finally get around to learning Irish after twenty years of dicking around, but I really think that's a fluke and not to be taken as a valid precedent for other cases. Same goes for Armenian, and possibly Persian as well (though I think I could make some real progress on that if I ever knuckled down and bought some quality texts; after all, it worked to a degree with Hindi).

Of all the dialects you could pick, why that one?

Mandarin
Basque
Finnish (even though it's on my list, I'll probably never get to it)
Swahili (see above)
Icelandic

Because its sound is awesome, actually, that's what I was originally expecting to find in Arabic, for some strange reason... Unfortunately, its sound is the only reason why I would learn it...

Me, too. I'd love to learn that 1 but I doubt I ever will.
Others for me include: Manchu, Evenki, Coptic, Sanskrit, Akkadian, & Māori. All of those are either extinct or endangered & that's 1 of the primary reasons why I probably won't get to any of them. Actually, I already dabbled a little bit into Manchu, Coptic, Sanskrit, & Māori but I quickly abandoned them.
Out of all those, Sanskrit seems the most likely, followed by Coptic & Māori. With Māori at least there's plenty of media. But even then I'd hardly have a use for it.

I would like to learn Sanskrit, but could not. Learning Sanskrit Could open up a whole new world for me that is full of treasure.

Something outside of IE. I study German, French and Irish, so something outside of the IE family will probably be next on the list. I don't have any motivation to learn any language outside of IE for the moment, so I will wait and see.

Other than that, I would like to learn some Ancient Greek and Latin.