I imagine the team was familiar with writing Java, which makes moving to Scala the easiest possible language transition besides maybe a move from C# to VB.NET.

I imagine the team was familiar with writing Java, which makes moving to Scala the easiest possible language transition besides maybe a move from C# to VB.NET. Switching to a completely different ecosystem, such as to R, Racket, Haskell and C takes at least twice as long. And could be much longer if you're relying on large framework changes, for instance if you're switching from QT to GTK+ or WPF.