제일 좋아하는 단어
저는 한국어 공부하기 두월 동안 만 했으니까 많은 단어를 몰라요.
단어 배우는 것을 너무 힘들어요. 그래서 제일 좋아하는 단어가 없어요. 저는 많이 공부해야 하라고 생각해요. 저는 한국어로 쓰고 읽어면 배울 수 있어요.
I've only been studying Korean for about 2 months, so I don't know many words.
Learning vocabulary is really difficult for me. That's why I don't have a favorite word. I think I need to study more (than I do now). By writing and reading in Korean, I can learn more.
제일 좋아하는 단어
저는 한국어 공부
하기 두월 동안 만 했으니까 많은 단어를 몰라요.
So, I made a lot of corrections here. It's probably going to be hard to follow but I'll try and explain each correction separately so bear with me.
1. 두월 is wrong.
First, 월 is not a counter for months, you can only use it ordinally (i.e. Jan, Feb, Mar...)
Plus, even with 개월 (which is the counter version of 월) it would be 이 개월/2개월 (the space is mandatory for the prior!) not 두 개월.
The counter you're looking for here is 달. 한 달 두 달 세 달.
2. "한국어 공부하기 두월 동안 만 [sic] 했으니까" is grammatically correct (except for the 두월 part and the space before 만). However, that isn't how the sentence would be expressed in Korean. How it would be expressed is:
한국어를 공부한 지 두 달밖에 안돼서
The grammar points you'd need to check out to grasp this construction are ~ㄴ 지 (지 is a boundnoun that refers to the time that passed since the event described in the previous clause happened. ㄴ 지 and ㄴ지 are different, notice the spacing!) and 밖에 ("negative" counterpart to 만). Also, you'd need to know 되다 (and 안되다, the negative form. notice the lack of a space) which is a verb meaning a certain state, time, or degree was reached.
3. 많은 단어를 몰라요 is a bit tricky for an English speaker, but check this out. Here, 많은 modifies 단어. So, if we were to group 많은 and 단어 together, that would be "[많은 단어]를 몰라요."
This means you don't know [a lot of words], i.e. there are many words you don't know. It emphasizes the many words you don't know.
However, in this situation, you're wanting to say that there aren't many words you know.
So, you have to use the adverb form 많이 so that it modifies the verb instead.
It then becomes something like "Words, I don't know many [of them]," emphasizing the fact that there aren't many words you know.
Hopefully you see the difference. Honestly, this is all kind of... If you don't see the difference, that's fine because I barely see it myself. Just know that you use 많이 모르다.
단어 배우는 것
을 너무 힘들어요.
Learning words is too difficult.
[Learning words] is the subject.
그래서 제일 좋아하는 단어
공부해야 하라고 생각해요.
or: 저는 많이 공부해야 한다고 생각해요. is fine too. But that just means "I think I should study a lot." not "I think I need to study more." The ㄴ다고 생각해요 is a bit unnatural, I think ㄹ 것 같아요 is better there too. A bit nitpicky.
저는 한국어로 쓰고 읽 어면 배울 수 있어요.
저는 makes it sound like you're the only one who can learn Korean by reading and writing. This is a general statement, so no need for having 저 in there.
Omitting objects is often fine. Here, I felt it was better to not omit them.
It's 으면 not 어면.
Two or more people need to make corrections in order for the corrections to be grouped.