I do believe, by the way, that for us native Hebrew-speakers, Arabic is one of THE EASIEST Languages to learn, what with it sharing SO MUCH vocabulary and basic grammatical structure with Hebrew (especially our mad verb-system). Next I would put the Latin Languages – with Spanish being the easiest to learn, followed closely by Italian – and then, assuming one already speaks good English, Dutch and Swedish are very very easy – while German, on the other hand, is still rather difficult and takes A LOT more time to learn.
By the way, had English been A PHONETIC Language, it would have A LOT easier to study than it is!!!! As things are, it is school-pupils' number one nightmare, SOLELY due to its TOTALLY insane writing-system.
On the other hand, the most DIFFICULT Language to learn – many people here, would say it's either Chinese or Hungarian. Well, I've never tried Chinese, but Hungarian, while difficult for sure, is still very Phonetic and LOGICAL (as opposed to English…), so it was not wildly difficult for me while studying it…
But, from my own personal experience, THE Most Difficult Language, the one that is A LOT more difficult than ANY other, is Czech. Specifically Czech, far more even than other Slavic Languages I have personally tried (such as Russian and Polish). Czech is, positively, INSANE.