-In string STR1, skip the first START1 characters and stop at END1.
-In string STR2, skip the first START2 characters and stop at END2.
-END1 and END2 default to the full lengths of the respective strings.
-
-Case is significant in this comparison if IGNORE-CASE is nil.
-Unibyte strings are converted to multibyte for comparison.
+The arguments START1, END1, START2, and END2, if non-nil, are
+positions specifying which parts of STR1 or STR2 to compare. In
+string STR1, compare the part between START1 (inclusive) and END1
+\(exclusive). If START1 is nil, it defaults to 0, the beginning of
+the string; if END1 is nil, it defaults to the length of the string.
+Likewise, in string STR2, compare the part between START2 and END2.
+
+The strings are compared by the numeric values of their characters.
+For instance, STR1 is "less than" STR2 if its first differing
+character has a smaller numeric value. If IGNORE-CASE is non-nil,
+characters are converted to lower-case before comparing them. Unibyte
+strings are converted to multibyte for comparison.