Wow, it's been a while. I've been doing an intensive music workshop this past week... Not relevant but yeah, that's what I've been up to instead of posting more glorious worldbuilding. Fortunately I'm back with more! This time... language! I would be OVER THE MOON if Odin/WAAARGHbobo were able to help me out with this, since we don't know much about many of Runeterra's languages other than Buhru. As a result I've had to mainly focus on different champion and character names to work things out instead of using the stuff I've learned in the linguistics class I took not too long ago.
**Common Languages:** There is likely not a "common" language, but there may be some varieties of pidgin for universal communication. The most developed of these would probably have been born in Bilgewater, the mother of all melting pots.
**Buhru:** “Words are built on combinations of Aztec and Ancient Greek, with additional elements of Hawaiian, Aboriginal Australian, and Latin.” This is our Buhru goldmine from Odin: https://boards.na.leagueoflegends.com/en/c/story-art/OPkqt6tg-waaarghbobo-you-say-you-work-on-champion-languages?comment=00000001000000000000
**Ionia**'s got... actually, a myriad of different languages. EDIT: There are several vastayan languages, but the only one we know (Baraashi, the Lhotlan tongue) is actually loosely based on Finnish. from Odin - "This was a combination of Sanskrit, East Asian and Slavic languages." Then there's the humans' tongue, we'll just call it Ionian. Ionian has several dialects that may sound different between groups, but are mostly mutually intelligible. So some dialects may be more nasal with shorter words and/or cleaner syllables, like Chinese, Japanese, or Korean (Irelia might speak one of these dialects), but someone like Karma might speak a dialect that might use the same/similar syllables but be more fluid.
**Noxus** has Va-Nox. Hey, at least we know the name of the damn language. There are several other tongues spoken within the realm's boundaries, but Va-Nox (and its older counterpart Ur-Nox) is the tongue of Noxus Prime. This one is tough though. Cassiopeia and Katarina are Greek names but they have a French surname, LeBlanc’s a French surname, Jericho is a biblical reference, Darius is a Persian name, Draven is made up, Vladimir is Russian, and Riven, Talon, and Sion are pretty much plain English. All. Over. The. Place. It makes sense that Va-Nox would be a melting pot considering the sheer size of Noxus's territory, but Ur-Nox is probably a lot of shorter syllables that may have some real-life influences in the Middle East. I will say this: if there's any language that is most likely to behave like the glorious mess that is English, it's Va-Nox!
We know nothing of the **Targonian** language other than its champions' names, which are almost unanimously Greek - even Zoe! (Diana and Aurelion Sol have Roman-derived names.) Targonian probably sounds pretty Hellenic as a result, though we also have stuff like Ra’Horak which is basically just Egyptian.
**Demacian** is oddly tricky to guess. Most place names and surnames are English, but names vary from Romance languages to German-ish (Garen and Lux's parents - Pieter and Augatha) to Quinn. Which is an Irish name. I have no idea what to do with this.
I wouldn't be surprised if the **Piltovan** language were something of a melting pot considering its origins. It seems pretty similar to Demacian at first glance. The aristocratic houses have a lot of Italian-ish names floating around (e.g. Jago Medarda), with some other Romance languages also thrown in the mix (e.g. Camille being a French name). Everyone else (like Caitlyn and Jayce) mixes it up; there are presumably Piltovan terms and names from all over the place because of immigration to the city. **Zaunites** probably speak a rather bastardized version of Piltovan.
**Shuriman** has mostly Arabic influences as far as I know, though I could be missing some info.
**Freljordian **has definite Nordic influences. Ornn's teaser song is in "ancient Freljordian," which turned out to make sense in a number of Scandinavian languages. No surprises there.