Final answer:
A compiler is the language translation software program used to convert source code into a machine executable program.
Step-by-step explanation:
The language translation software program used to convert source code written by programmers into a machine executable program is a compiler. A compiler takes the entire source code as input, analyzes it, and translates it into machine code that can be executed directly by the computer. It checks for syntax errors and generates an object code file, which can then be linked and converted into an executable program.