To quote Joe Armstrong: "As Erlang became popular we were often asked "Is Erlang OO" - well, of course the true answer was "No of course not" - but we didn't to say this out loud - so we invented a serious of ingenious ways of answering the question that were designed to give the impression that Erlang was (sort of) OO (If you waved your hands a lot) but not really (If you listened to what we actually said, and read the small print carefully)."
Erlang is closer to original Smalltalk than most of current OO languages: there are processes (objects) which communicate by messages (messages).
I also should mention OOHaskell: http://homepages.cwi.nl/~ralf/OOHaskell/ "In the second and major phase, we systematically substantiate that Haskell~98, with some common extensions, supports all the conventional OO features plus more advanced ones, including first-class lexically scoped classes, implicitly polymorphic classes, flexible multiple inheritance, safe downcasts and safe co-variant arguments. Haskell indeed can support width and depth, structural and nominal subtyping. We address the particular challenge to preserve Haskell's type inference even for objects and object-operating functions. Advanced type inference is a strength of Haskell that is worth preserving. Many of the features we get ``for free'': the type system of Haskell turns out to be a great help and a guide rather than a hindrance."
So everyone "can has" his OO everywhere, in case one needs it.
Don't really know Erlang, but having worked for Telecom industry earlier, I would guess Erlang is getting its concepts and messaging model from SDL [1] rather than from OO.
http://www.sics.se/~joe/bluetail/vol1/v1_oo.html
Erlang is closer to original Smalltalk than most of current OO languages: there are processes (objects) which communicate by messages (messages).
I also should mention OOHaskell: http://homepages.cwi.nl/~ralf/OOHaskell/ "In the second and major phase, we systematically substantiate that Haskell~98, with some common extensions, supports all the conventional OO features plus more advanced ones, including first-class lexically scoped classes, implicitly polymorphic classes, flexible multiple inheritance, safe downcasts and safe co-variant arguments. Haskell indeed can support width and depth, structural and nominal subtyping. We address the particular challenge to preserve Haskell's type inference even for objects and object-operating functions. Advanced type inference is a strength of Haskell that is worth preserving. Many of the features we get ``for free'': the type system of Haskell turns out to be a great help and a guide rather than a hindrance."
So everyone "can has" his OO everywhere, in case one needs it.