So, to simplify:
- Everyone has a 1 in 6 chance of knowing any language, modified by intelligence bonus and language skill.
- Every character has a mother tongue.
- When you roll to see if you know a language, count the jumps between your mother tongue and the new language. That is your penalty to the language roll.
- If there is no connection, it is a dead or totally alien language and you get minus 6 to the roll.
The connections represent logical connections rather than common linguistic roots. Sokone isn't closely related to Yongardy or Calipygeon, but they interact a lot and would be commonly shared. Kairn has no relation to any of the other languages, but they live right in the middle of everyone so some cultural exchange has to happen.