What is the most difficult language?

What is the most difficult language?
I have experience studying English, French, Spanish and Russian. For me, Russian is the most difficult because alphabet is difficult. I'm Japanese, so I have some experience with teaching Japanese. I often thought (I've often thought or I often think) that Japanese is difficult even though I'm (when talking about ethnicity you don't need to use a or the unless you say I am a Japanese person) Japanese.
What is the most difficult language in your case?

I think German is really difficult because of the grammar rules. I also lived in Cambodia and tried to learn Khmer, but it's very confusing! The alphabet is so long, and all the letters look the same to me!

Okay, so I'm no expert in spanish, but I do know this. You use buena with feminine words (la words) and bueno with masculine words (le words). Feminine words tend to end in -a but there are exceptions. Dia ends with -a but is a masculine word. So you say buenos dias not buenas dias.

It's pretty tricky. Each set of synonyms carries a different connotation that is hard for a non native speaker to understand. I think the best way is to practice you English, ie speaking or watching a movie, and see how native speakers would use it. For example, with the sentences you wrote, freaked out and shocked sound very similar in definition, but as a native speaker, I see them as two completely different things. If you are shocked, that means that you are very surprised. If you are freaked out that means that you are surprised but also scared. If you see a massive spider, it may freak you out. If you are not afraid of the spider, you may still be shocked that the spider so big. It doesn't scare you, you've just never seen such a big spider. Hope that helps :)

Yes, a residence hall room would be a room where one or two students live in at the university. I have actually never heard this word, but I am American so that might be why. They are also called dormitories or dorms for short.

In both sentences you should say didn't instead of hadn't. Other than that it's perfect :)

To my knowledge there isn't a way to do this on any site. I think the reason is that there isn't that much of a difference between British and American English. Sure it's not the same (different pronunciation, a few different words), but we still understand each other. From what I understood, there is a bigger difference between Portuguese in Portugal and Brazilian Portuguese. I could be wrong, but that seems like the reason. So as far as I know, no one dubs American movies with a British accent.

I would suggest writing a text on Italki and then asking people to correct the punctuation. The rules are pretty immense, so I think that practice would be the best way to learn. :)