For example, keywords have a special prefix. Objective-C has `@interface`, `@implementation`, but that's for compatibility with C. It inherits all the C keywords of course, with no `@`.
How about a language in which all keywords are prefixed with a special character? It'll save the lexer some trivial trouble, but the programmer finally gets to use the words `float`, `class`, `template` ... etc.

Contrarily, C# allows @class as variable name, but that's no different from using class_.