The same principle applies when switching between different programming languages. When switching between projects, you need to juggle between different contexts; when switching between languages, you need to juggle between different syntax, data structures, and ecosystems. To demonstrate, the following table illustrates some key differences between Python and JavaScript:
| Python | JavaScript |
| Has many data types, including None, Boolean, int, float, complex, list, tuple, range, str, bytes, bytearray, memoryview, set, frozenset, dict, and many more | Has seven data types: undefined, null, Boolean, number, string, symbol, and object |
| Statements are grouped by indentation | Statements are grouped by blocks, expressed using enclosing braces ({}) |
| Uses virtualenv to create isolated environments | Uses Node Version Manager (https://github.com/creationix/nvm) (nvm), package.json, and the local node_modules directory to create isolated environments |
| Uses a class-based inheritance model | Uses a prototype-based inheritance model |
In addition to syntactical differences, different languages may also follow different paradigms—Elixir is a functional language, whereas Java is an object-oriented (OO) language.
Therefore, context-switching between different languages also makes the development process very inefficient.