>>1
There is no answer to this question. All languages have their own complexities, and from a strictly linguistic perspective, are about equally difficult to master. But I'm a native English speaker, have studied many languages, and can speak six comfortably.

In my experience, the Austronesian languages (Indonesian/Malay and related tongues) are some of the simplest to get started with. They use the Roman alphabet, exhibit regular, phonetic spelling (so you can always tell how to pronounce something by the way it's spelled, unlike with English) and do not decline at all (so words don't change to mark conjugation, tense, or number). It makes it quite easy to begin speaking.