Compare static and dynamic typing, and gradual typing systems.

Static typing (Java, C++, Go): types checked at compile time. Benefits: early error detection, IDE support, optimization. Cost: verbosity, less flexibility. Dynamic typing (Python, JavaScript, Ruby): types checked at runtime. Benefits: flexibility, rapid development, duck typing. Cost: runtime errors, less tooling. Gradual typing (TypeScript, Python type hints, Flow): optional static types layered on dynamic language. Best of both: type where beneficial, dynamic where flexible. Type inference: compiler deduces types (Kotlin, Swift, TypeScript). Structural vs nominal: TypeScript structural, Java nominal. Trade-off: safety vs flexibility vs developer experience.