Jongwoo:

Purposefully teaches you weird and bad words. So now don't ever trust him to help you translate something to a stranger. When he has to help you actually translate a word suddenly he forgets his own language and just ends up going; "eeuhm... It's... I guess you could use... euh... like...".

Talking in English is awkward for him as he isn't the best in this area so very stiff and unsure when he has to speak English.

Moonjo:

Helps you learn the language accurately, teaching you so well you would have mistaken him for a teacher instead of a dentist. He likes to randomly quiz you by motioning to items in a store or wherever and have you say the right Korean word for it.

He can easily communicate with you in English but he tries to stick to only Korean so you will learn it faster.

Junghwa:

She has hung up so many sticky notes for you in the house that you can't look at a single area without seeing one of those damn yellow square notes. It is helpful, though. She'll play many boardgames with you, where you may only speak Korean. Anyone who dares urge you to hurry she's quick to tell them to be patient and instead be appreciative instead of complaining when you are willing to learn their difficult language.

You learning her language, one of the hardest languages to learn for English speakers, so she'll learn yours to show the same respect, both feel bonded in struggling, and because she actually does want to learn more languages.