I'm quite exposed to different languages like English, Spanish, Japanese, and Korean. Putting English aside, I think Japanese is the easiest for me to learn. I love how their syllables are not complicated and you can even learn the basics of the language on your own. I've tried that before through some websites and it worked. However, since I didn't actually use it, I somehow forgot most of it. But, yes, in my opinion, I think Japanese is pretty easy.