2ヶ月でこんなにできるなんてすごい

Question

I posted on an app a self introduction message, and I mentioned that I'd been studying Japanese for two months, one of the comments was this:

2ヶ月でこんなにできるなんてすごい！！

I get that the general idea is that she is impressed by my Japanese after only two months of studying.

First question, am I right in assuming she is using で as a particle here? I thought you only used it after locations. I've never heard of "dekonnani" before.

Second question, is なんて a typo? Did she mean to say なんで?

A full sentence breakdown would be awesome.

Answer 1

「[2ヶ月]{にかげつ}でこんなにできるなんてすごい！！」

2ヶ月で = within two months

こんなに = like this, this much, to this extent This phrase functions adverbially to modify the verb 「できる」.

できる = to be able to (use/speak/write Japanese)

なんて = 「なんて」 here introduces a topic/thing that is surprising or unexpected to the speaker. Here, that topic/thing is your Japanese proficiency.

すごい = (it is) awesome

「なんて」 is a key word here and so is 「できる」.

Answer 2

I'm going to provide this as an answer, although I'm by faar not the most experienced with Japanese. So take this with a grain of salt until one of more knowledgeable ones gives a better answer.

What scrubs like me tend to do is input the sentence being translated over into www.jisho.org. That segments the sentence properly, most of the time.

As such, I'd segment it like this:

2ヶ月で = two months, with で being there to indicate the time of action, as is one of it's dictionary defined duties as particle. I wonder why there isn't anything to indicate that this is AFTER, but eh. It could though also mean that this is "due/because of two months". As in the later bit is consequence of the two months (of studying). But that is a bit of a guess.

こんなにできる is composed of adverb meaning so/like this/in this way and verb "to be able". Meaning is clear "to be able to (write) like this" and write/speak is I guess the context here.

Now before tackling the なんて but BIG parentheses around the preceding bit, because as others have pointed out it's there to provide equivalence between parts on either side of it. That is it means such.

And it ties to the adjective for wonderful. So you have

Being able to (write) during/at/because of two months | such is | wonderful

So (reading it backwards, which sometimes helps, but is not really needed here):

It's wonderful that you are able (to write) like that after two months.

Aaaand there goes a better answer while I was composing this rambling one.