

No but seriously I think you can't really give any objective answers to the question in this thread... the degree of difficulty involved in learning any particular (foreign) language is a subjective matter and depends on various factors (your motivation, your native language, the learning environment, and so on)...
However what never ceases to amaze me is the ability of young kids to learn a foreign language without really trying at all (or at least it seems that way). Many many years ago a neigbour married a Norwegian, she had one daughter from an earlier marriage, maybe something like 5 - 6 years old when they moved to Finland. A couple of years of exposure and the girl's Finnish was so perfect you could barely tell her native language was Norwegian.
Alas it's tougher for us older people - I'd love to learn Russian or Portuguese for example, but it appears a really daunting task in all respects. Quite possibly the batteries of my Language Acquisition Device are running low!