Easiest conlang that is also very "complete"

Is there a conlang out there whose sole design intention was to be the easiest language to learn while still being fairly complete in terms of ability to express one's thoughts ?

I was thinking about this - languages are very fundamental to human minds and society as a whole, they are the medium through which two minds connect.

Similar to other avenues of life, there must have been at least some attempts at simplifying and sort of making a language that is more ideal/practical in its mechanics than the real, organic languages .

Asking just out of curiosity, nothing against conlangs that are trying to seem organic or anything like that.

Edit: spelling fix