M Glasser10,867 Points
What makes something a "true" object oriented language?
What does he mean exactly?
Steven Parker171,091 Points
The classic definition is that there are 4 major principles that make a language object-oriented: Encapsulation, Data Abstraction, Polymorphism and Inheritence.
Recent language additions (ES2015/ES6) have closed the gap bit by introducing keywords and syntax much like class-paradigm languages, but there still are differences including the lack of abstract classes.