Korean: native but kinda got weird due to so many years spent overseas. I’m still baffled that there is no Korean language support for this game for playstation!
Japanese: almost native speaking and listening, but apparently reading and writing is at 5th grade level.
English: poor. When npcs talk to each other I have no clue what they’re saying. I just know that same 3 or 4 voice actors must be doing all npc conversations.
i’ve heard how peoples own language and way of speaking changes over time if they stay in a place long enough they find it weird speaking their mother tonuge.
He could be a Djibouti 
The hardest regional language to learn is definitely west country accent, i’m from there, so im used to these examples:
'Ark at he (Your to talk)
Your gurt lova (You alright love)
Skew-whiff (Crooked)
Where be to? (Where are we/Where are we going)
This is a great example of any person who is native to the west country and is over the age of 55 (great movie btw):
https://www.youtube.com/watch?v=Hs-rgvkRfwc