I can't tell if you're joking or not. Why would I delete the source code of every program after writing it?
I mean, delete the source, but store an intermediate representation that can be decompiled into any other language for reading.
Languages with good type systems and tooling support a workflow where you mostly rely on Intellisense hints and docs, and never read the code itself.
That, but taken to its logical conclusion: if you never read the source code, you don't need to store the source code.
The missing part is the ability to define algorithms as modifications of existing algorithms.
The choice of the language would become a matter of presenting the compiled code and writing replacements for new code.
The runtime and the type system can't be replaced this way though.