The hardest language in the world?

I am always studying languages, but then I lose interest right away. However, I have to agree that Japanese is not that difficult to learn, if you are a dedicated person and really try your best to learn it. I learned all hiragana and katakana within 2 months or less.
But, anywayth...I have to say that Vietnamese seems hard. I used to have a friend that was vietnamese and she would teach me, I kept on trying and trying to master the pronunciation, and I did, but I always forget.
Plus, there are a lot of accents that I think is so confusing. And, it's not pronounced as it is written, like Spanish or Italian. The word Chao is pronounced like Gaoh. I must say that it was a challenge for me. ^_^

I was speaking idiomatically.