What languages are magic runes written in?

[Lupine]

In the MM, the hags, who often do rune magic (under their entry in Volo's, a small side note in the weird magic section) speak many languages. What languages are magic runes written in?

Also, to the side, if you'd give me some ideas of weird magic for green hags and Bheur hags, that would be useful, but please focus on the main question.

EDIT:
Now that I have gotten a good idea of what to use for runes, I would like some ideas for weird magic.
Thanks to those who got me such a quick response.

[JackPhoenix]

It doesn't have to be language. If you consider symbols used in real esoteric practices (say, zodiac signs) comparable to "magic runes", they don't really have meaning that would allow you to use them as an alphabet for a proper language. They are just mystical(y looking) scribbles.

[Unoriginal]

In the MM, the hags, who often do rune magic (under their entry in Volo's, a small side note in the weird magic section) speak many languages. What languages are magic runes written in?

Also, to the side, if you'd give me some ideas of weird magic for green hags and Bheur hags, that would be useful, but please focus on the main question.

Magical writing is basically personal shorthands for your own conception of magic. That's why you have to decode another caster's notes then re-copy them in your own shorthand to be able to use the spell, if you're doing wizardry.

Runes are what the Giants' and Dwarves' alphabet is called, though.

[Quoxis]

Weird magic, according to volo‘s, can be magical effects that aren’t covered by spells available to normal beings.
Possible ideas:
- small insignificant effects akin to prestidigitation/thaumaturgy
- effects from magic items (turn a twig into a snake, create water/turn a 10ft cube of the ground the rune is carved into to water)
- any effect from the wild magic table from the phb (step on a rune, and congratulations, you are now a plant for 1d10 rounds)
- something wicked, but not gamebreaking (you step on a rune, now something about your main playstyle changes for 1d8 rounds - your +2 shortsword is glued to its scabbard and can’t be used; your damaging cantrips require a coinflip at each use, and while heads does the normal damage, tails instead heals the target for the same amount; you can’t use damaging xth level spells, but all spells of lower levels are upcast as xth level (beware of my 7th level magic missile!); your shield grows sharp edges and each thwarted attack targeting you instead hurts you for 1d10 slashing damage, but you can use it as a weapon for 1d10 damage or drop it...)