Unity, a popular game development platform, supports both C and JavaScript as programming languages. However, there are some key differences between the two that can impact your choice of language for your project.

C is a statically-typed, object-oriented language developed by Microsoft. It is used extensively in Unity’s scripting layer and is considered the primary language for game development with Unity. C provides a wide range of features such as support for multiple inheritance, interfaces, delegates, and garbage collection that make it a powerful language for building complex applications.

JavaScript, on the other hand, is a dynamically-typed, scripting language used extensively in web development. While it can be used with Unity through plugins and external tools, it is not as commonly used as C for game development due to its limitations in terms of performance and complexity. JavaScript lacks many of the advanced features provided by C, such as multiple inheritance and interfaces, making it less suitable for building complex applications.

In conclusion, while both C and JavaScript can be used with Unity, C is considered the primary language for game development due to its superior performance, complexity, and range of features. However, if you are more comfortable with JavaScript or prefer to develop games using web technologies, it may still be a viable option for your project.