English takes no skill to speak.

Seriously, some of the dumbest people in the world speak it. It takes no skill to speak. Whereas other languages such as Русский, Español, Tiếng Việt, 日本語, 汉语, 한국어 and several others require skill. I'm sick of hearing this comment about how English is one of the most difficult languages in the world. It's the easiest. Anglophones are also some of the most ignorant and obnoxious people in the world.

Ithkuil is the hardest language.

Go fuck yourselves now.

Seriously, though, the difficulty between languages can't be measured by a single factor. You need to take so many things into account; case system, verbal system, phonology, morphology, arbitrariness, et cetera, et cetera.

English is my third language, and by personal opinion, I find it far easier than Russian, my first, and German, my fourth.

Russian has a far more complex verb system than English, as well as a large amount of consonantal phonemes (due to palatalisation and such) and far more difficult grammar.

I know Norwegian, as well, and find it stupidly simple. Simple "subject-object" case system, relatively small vocabulary, etc. Pronunciation is on the irregular side, but it's still no big deal.