Welcome to learning Korean! Here I provide beginner Korean study material to get you started out with learning the language. With basic grammar, key vocab, and more to help you along the way.
I remember really having an issue with sino vs native korean numbers and this is a recourse I found that can really help you out if you find yourself in the same position! You can play through 1-100 on both the sino and native korean numbers games for a nice review and test on your skills.
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.