Multiple programming languages can be embedded and supported within a single source. Programs nested with syntax from a plurality of languages (e.g., C#, SQL, XML . . . ), among other things, enable users to avail themselves of advantageous aspects of different languages for particular tasks. Language services that provide language specific functionality including but not limited to formatting, intelligent assist, auto completion, and coloring, can be employed and switched between to afford support for their respective languages in a mixed language source program. Similarly, mixed language programs can be compiled with language specific services or systems such as parsers, scanners and the like to process corresponding code portions.