[regularfry]

That's not quite fair. Erlang was designed from the start to be very, very fast at process switching and message passing. True, that design took a while to bear fruit, but my understanding (from listening to Joe Armstrong speak about it) is that being able to make the core of the language highly efficient was a goal from the start.

[forensic]

Trying to make it as efficient as possible is different from the purpose of the language being efficiency.

[regularfry]

Indeed, but in this case both apply.

EDIT: Give this a listen, the early design and development is described in more detail than I'm capable of going into: http://www.se-radio.net/2008/03/episode-89-joe-armstrong-on-...