Drake supports "protocol" abstraction, which is much more than just specifying an interpreter. Python is a trivial protocol, not much more complicated than shell. There are slightly more complicated protocols, for example, "eval", which runs the first line as a shell command before putting everything else in $CMDS environment variable. There could be protocols for running an HBase query, a Pig query, Cascalog query, or an SQL query. Some of these things could involve building a JAR file and giving it to Hadoop binary. Currently only a handful of protocols is implemented, but more are described in the spec.
