+The second form is used when retrieving translation of string that has
+different singular and plural form in English or different plural forms in some
+other language. It takes two extra arguments: \arg{str}
+parameter must contain the singular form of the string to be converted.
+It is also used as the key for the search in the catalog.
+The \arg{strPlural} parameter is the plural form (in English).
+The parameter \arg{n} is used to determine the plural form. If no
+message catalog is found \arg{str} is returned if `n == 1',
+otherwise \arg{strPlural}. The \helpref{ngettext}{ngettext} macro is defined
+to do the same thing.
+See \urlref{GNU gettext manual}{http://www.gnu.org/manual/gettext/html\_chapter/gettext\_10.html\#SEC150} for additional information on plural forms handling.