In Pharo everything is an object. Compiler - object, network - object, method - also an object. And objects communicate with messages. No operators, no control-flow statements. Just objects and messages. Few things to learn, but you can learn OOP well.

There is good, free documentation including several books written by experts with extensive examples. There is an online MOOC. There are many tutorial videos. Supportive conferences and community. Even a professional support option if desired.

Smalltalk isn't very used in industry, but is excellent for the personal grow of the programmer.