Q: I'm starting to think about multinational character sets, and I'm worried about the implications of making sizeof(char) be 2 so that 16-bit character sets can be represented.
A: If type char were made 16 bits, sizeof(char) would still be 1, and CHAR_BIT in <limits.h> would be 16, and it would simply be impossible to declare (or allocate with malloc) a single 8-bit object.
Traditionally, a byte is not necessarily 8 bits, but merely a smallish region of memory, usually suitable for storing one character. The C Standard follows this usage, so the bytes used by malloc and sizeof can be more than 8 bits. [footnote] (The Standard does not allow them to be less.)
To allow manipulation of multinational character sets without requiring an expansion of type char, ANSI/ISO C defines the ``wide'' character type wchar_t, and corresponding wide string literals, and functions for manipulating and converting strings of wide characters.
See also question 7.8.
ISO Sec. 220.127.116.11, Sec. 18.104.22.168, Sec. 6.1.4, Sec. 7.1.6, Sec. 7.10.7, Sec. 7.10.8
Rationale Sec. 22.214.171.124
H&S Sec. 2.7.3 pp. 29-30, Sec. 2.7.4 p. 33, Sec. 11.1 p. 293, Secs. 11.7,11.8 pp. 303-310