A system that executes a program is called an interpreter of the program. Loosely speaking, an interpreter actually does what the program says to do.
This contrasts with a language translator that converts a program from one language to another. The most common language translators are compilers.
Translators typically convert their source from a high-level, human readable language into a lower-level language (sometimes as low as native machine code) that is simpler and faster for the processor to directly execute.