My Ancient Hebrew professor would lose himself at the whiteboard. He'd be teaching and say, “I wonder if this is related to…” then scribble something that definitely wasn't Hebrew in a corner of the board. He'd realized some potential overlap between Hebrew and one of many other semitic languages. Eventually he'd remember the students behind him.
I'm working on a game set in the Ancient Near Eastern underworld. I want to simulate related language families. Are there different Elvish dialects? Is Dwarvish similar to Goblin? I don't know, but with this system, they could be.
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All sentient non-human creatures of the Underworld understand all languages. PCs share 1 language. All other Living and Dead have a language assigned by 1d6 when met. Roll once for a group. Languages are on a continuum. 2-3 are adjacent, as are 6 and 1. Characters understand their language and the adjacent languages (Dialects) without trouble. Languages 2 away (Cognates) allow communication when Spending Time to communicate. The language 3 away (Foreign) is hopelessly remote; only gestures and proper nouns can be exchanged.
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1-2-3-4-5-6-1-… 1 and 4, 2 and 5, 3 and 6 are foreign to each other. This setup allows broad communication with some difficulty and occasional instances of unintelligibility.
If you aren't too strict about each language die result corresponding to a specific language, you could use this as a simulation of language proficiencies. 1’s live near Giants so know their language almost natively. 2’s know Goblin and Giant but have no dealings with Elves, who are around 5. 3’s know Common and Goblin well but not Giant.