What is Erlang written in?

Question

What is Ericsson\'s implementation of Erlang and Erlang/OTP written and compiled in? Is is assembly, C or Erlang itself?

Update 1: Thanks to DrJokepu. If I understan

Answer 1

I can say that Erlang was initially written in C/C++ as I can't say that Java is written in java.... but It's framework and Some libraries. About Erlang, As Its is preferred programming language and suitable for Telecom system... in order to maintain swiftness (e.g: in chat-bots) I know that its compiler or PreProcessor is written in Erlang. But Other features of language are written in Low Level languages.