# Types in the Nu Language
## Overview
Nu is strongly typed and gradually typed.
- **Strongly typed:** Types are strictly enforced.
- **Gradually typed:** A mix between static (types are checked at compile time) type checks and dynamic (types are checked at runtime).
Gradual typing is a clarification of optional typing where the developer could choose or not choose to add type annotations to declarations. This paper from Jeremy Siek is here: [What is Gradual Typing?](https://wphomes.soic.indiana.edu/jsiek/what-is-gradual-typing/)