As a computer scientist, RStudio's Joe Cheng has some great insights into the R language and how it compares with other programming language. In the interview with DataScience.LA below, he notes that while R is often thought about as a domain-specific language (or DSL), the combination of a functional language with deferred evaluation of functional arguments actually makes it a great general-purpose language for implementing a statistical DSL.
Also of interest in the video is Joe's description of the genesis of Shiny at useR! two years ago (the idea of a reactive framework for R literally came as an inspiration in his sleep!), and some of the technical underpinnings of the Shiny system which are generally useful for connecting Java and R.
DataScience.LA: A conversation with Joe Cheng at useR! 2014