Learn all about Korean culture while you learn the language! The two go together hand in hand; culture influences language and vice versa so it’s key to learn if you want to really understand Korean.
A lot of fans dream is to use Kpop to learn Korean, and while obviously that’s not entirely possible it can certainly help. I remember one of the first phrases I learned was “머리부터 발끝까지” or from head to toe because someone pointed out how common it was in songs!
Sino-Korean basically means that a specific words source is originally Chinese. About 60% of Korean has Chinese origins as a basis. Words like 인간 (person/human) use the Chinese character (or hanja in Korean) 人 make the 인 in 인간.
One thing about Korean many people struggle with is the dynamics between people and speech. For native English speakers; especially if English if your only language, formalities is something that doesn’t exist to a quarter of the extent as in Korean. Korean is a culture based highly around respect and knowing or understanding you position and others.
Now Koreans don’t solely use these terms for people related to them, they are used freely! People call the woman running the restaurant 이모, boys call their older friends 형, etc. These terms are used to show how close and familiar you are with others (and for the ‘aunt’ at your favourite K-BBQ to warm up to her and maybe get extra side dishes haha).
A lot of Korean texting slang has a rooted meaning in the original word, just shortened to make it easier to type. Some originate from Korean itself like 엉 which is the most casual way to say yes or yeah in Korean, being reduced down to just ㅇㅇ. Or ᄋᄃ from 어디 (where), ᄆᄎ from 미쳤어 (crazy), etc.