How many functional programming languages do you cross of the list of functional programming languages if you make that claim? At the very least anything Lisp related, all the ML languages as well. You are pretty much left with Miranda, Haskell, and a few related languages.
An FP language doesn't preclude non-FP code, just like OOP doesn't preclude ... procedural code? I'm not sure what the opposite would be but it exists (think Matlab code).
I would argue that the lisps are not very functional languages (both in the importance of effects and the style of code I've seen written in lisps), but Scala provides for a lot of FP assurances (val over var, good FP-y libs), and people in the community value effectlessness. So I'm comfortable calling Scala a FP language.
Functional programming used to mean programming with first class functions and closures; they even put it in the name "functional"al programming (just like OOP meant program with objects, whether this involved classes or not).
So that is Lisp, the first FP in the 60s, and then the MLs of the 70s/80s. They knew about purity, and even preferred it (for things like list comprehensions, it is very useful), but were never very dogmatic about it.
