The Korean language has an honorifics system, with a mandatory formal speech and an informal speech. Japan has a similar system, with a mandatory honorifics system. It's sort of like how in English, we have Mr/Mrs, your highness, etc. This is partially influenced by Confucian teaching to respect your elders, honorifics are highly important both culturally and linguistically. It's hard for people to wrap their head around at first, but you'll get used to it.