Having (mostly) learned how to navigate Python programming in GIS, I've gotten to thinking about where GIS programming is going from here. I know VB used to be the go-to language for ArcGIS, but that has been supplanted by Python. I love Python's utility, ease of use, and support in a variety of spatial and non-spatial programs, but I know these are no guarantee of it sticking around.
I'm curious about which languages I should keep an eye on and consider dabbling in to be ahead of the curve. I've seen a few options out there. For example Geoscript has libraries for Scala and Groovy in addition to js and Python.
What up-and-coming programming languages are trending towards increased use, increasing geospatial functionality, and cross-application scripting?