I would argue that C has no concept of a string: there is no direct support in C (or C++, for that matter) for concepts related to strings. They are just arrays that happen to contain characters. All of the strigyness of those arrays exists solely in the mind of the programmer. C itself does not help you any. That is, I think, the hallmark of a language level abstraction: does the language allow you to think of the entity only as its abstraction, or do you need to handle that yourself? This fact is also, I think, a major reason why there are so many string-related bugs in C code.

Having never used Common Lisp, I can't say if that's also accurate for your other example.

Edit: ARGH. I forgot string literals in C. So C clearly does have the concept of strings. The problem is that's the only support in the language for that concept. Aside from being able to define string literals, C does not help you with strings at all.