Kotlin creator Andrey Breslav has unveiled CodeSpeak, a new programming language designed to communicate with large language models using formal specifications instead of English. The language promises to shrink codebases by 5-10x through specification-driven development, targeting production-grade systems rather than prototypes.

CodeSpeak works in mixed projects where developers write some code manually while generating other components from specs. The tool includes a CLI for installation via uv and supports teams building complex software. Early case studies demonstrate dramatic reductions in code size while maintaining or improving test coverage across real-world open-source projects.

The approach represents a fundamental shift in software development methodology. Instead of maintaining thousands of lines of code, teams would maintain concise specifications that generate equivalent functionality. This could transform how engineering teams collaborate, particularly for long-term projects where communication overhead becomes a bottleneck.