I love the Korean Grammar in Use series of textbooks. You can purchase them from amazon.com or, for a lot cheaper, here: http://www.darakwon.co.kr/searching/?scate=&stext;=korean+grammar+in+use However, that would require using the site in Korean and I'm not sure about the shipping and handling fees. South Korea is pretty close to Viet nam though. Closer than to the East Coast of the US. I also adore these books from the Korean Ministry of Education designed for Koreans living in, well, not South Korean. You can view them online for free here: http://www.efka.or.kr/user/info/data.asp?leftNum=1 Other than that, as mentioned, I like talktomeinkorean.com, howtostudykorean.com, and so on for grammar. endic.naver.com is a great dictionary, and naver.com itself is an awesome resource. I do occasionally use dic.daum.net too for a dictionary. Then, more generally, there's youtube and tumblr (and other blog sites). I've used Monash University's site too before. Here's some free online books too: http://www.koreanlab.co.kr/main/index.asp?t_id=1

I'm not sure what kind of learner you are, so I can't guarentee anything. At the moment, I'm using a textbook called Korean From Zero and I really like it so far. The author has released a PDF version for free. (http://www.koreanfromzero.com/downloads/Korean_From_Zero_Book_1_2015-04-02.pdf) It goes through grammar and vocabulary and I found the exercises in the book to be quite effective when it comes to enforcing the content covered in the lesson. There is also an online course component and audio files, so be sure to check out their website: http://www.koreanfromzero.com/lessons/ Monash University also provides their textbooks and audio files for free: http://artsonline.monash.edu.au/korean/my-korean-1/ I have more resources, but I see that Tony has already given you a few others to try. If you need anything, feel free to message me. Good luck on your learning journey :D

Welcome to Korean, Lan Anh. In my opinion, you definitely need to do a good deal of reading and listening as well if you want to speed up learning. You can read children's tales, textbooks, and serious novels and other online texts as you get better. For listening I think radio and TV news are the best contents since they use the best language and cover broad subjects. To do it effectively you'll need to have good online dictionaries and grammar sites so you can look things up quickly. The browser-based pop-up dictionary (Toktogi below) is really indispensable for reading online as you can check the meaning of new words without leaving the page. Here's some resources: http://endic.naver.com/?sLn=en (full Kor-Eng dictionary) http://dic.daum.net/index.do?dic=eng (full Kor-Eng dictionary) http://www.toktogi.com/ (Toktogi popup Kor-Eng dictionary) http://dongsa.net/?search=%ED%95%98%EB%8B%A4 (verb conjugation lookup) http://www.howtostudykorean.com/ (grammar and general study) http://www.talktomeinkorean.com/ (grammar and general study)