And other say that German is the hardest one , and many say that about Greek its totally different than the whole european language which root mainly from Latin . But in my opinion that depend on everyone ; if u like any language and have a strong intention and motive it will be so easy if u haven't that it will be tha hardest ever .

They say Icelandic, but I think it may be something like Bulgarian or Finnish.

Honestly I can't say.. I think greek and hungarian are the most difficult european languages to learn.