What is hardest to learn?

[Cap]

Russian, Arabic, or Chinese?  I am thinking of going to a school or using Rosetta Stone.

[mass 04]

I tried to learn Arabic. It's tricky to say the least.

[Soundness]

Russian, Arabic, or Chinese?  I am thinking of going to a school or using Rosetta Stone.

It is much wiser to ask yourself, "Which one am I most likely to find the most useful in my lifetime?"
If you're going to put the time and effort into learning it, you certainly want to feel there is a future value for it.

My guess is that, living in the United States, you will find Chinese most useful in your lifetime of the 3 you've named.
Imagine the fine Chinese tail you could pull if you could impress them by speaking to them in their native language.  

[Cap]

I was thinking of learning one of the three to make myself more competitive for government jobs.  I've heard Russian is the least difficult but they all are hard to learn.

[garebear]

I was thinking of learning one of the three to make myself more competitive for government jobs.  I've heard Russian is the least difficult but they all are hard to learn.

I'm learning Chinese right now and is HARD. There are multiple aspects to it that you would never dream of if you grew up speaking English.

I think Arabic would be more difficult than Russian. At leat Russian has a predominately Roman alphabet, so you would have a good start there.

If you choose to study Mandarin, get ready to devote a large part of your time to it.

[Tombo]

It is much wiser to ask yourself, "Which one am I most likely to find the most useful in my lifetime?"
If you're going to put the time and effort into learning it, you certainly want to feel there is a future value for it.

My guess is that, living in the United States, you will find Chinese most useful in your lifetime of the 3 you've named.
Imagine the fine Chinese tail you could pull if you could impress them by speaking to them in their native language.  

aren't there multiple dialects spoken in China, all of them commonly used?

[garebear]

aren't there multiple dialects spoken in China, all of them commonly used?

there are multiple dialects, yes. Mandarin is the most common and it is universally taught to Chinese in school. It may not be their first dialect but 90 percent of China can speak it to a satisfactory degree.

Hong Kong and southern China also speak Cantonese. I think this would be the second best to learn.

but when people say "speak Chinese", they most probably are referring to Mandarin (putonghua).