Easy non-Romance languages?

Hi /lang/. English speaker here. Can you think of any languages outside of the Romance language family that could be classified as "easy?" I want to learn a language that has fairly good online documentation, isn't Swedish, German, or Dutch, and also isn't constructed. I know these are strict filters, but you guys ARE the experts.

OP, am I correct in inferring that you've a mind to learn a language just for the sake of learning it, and for the various benefits that are said to accompany bilingualism, other than the obvious benefit of being able to communicate with another group of people?

They say that the second language you learn is always the hardest, so mitigating that somewhat by "practicing" learning an easy language before you proceed to one you intend to use might well be a workable strategy. My understanding is that invented languages tend to be easier to learn due to their regularity, so you might start with one of those?