From what I've understood,
the current message doesn't address languages having 2 plural forms (+1 singular).
So, the solution in this case would be to accommodate a language which has special plurals for numbers ending in '1'.
But only [2-9]1.
http://www.gnu.org/savannah-checkouts/gnu/gettext/manual/html_node/Plural-forms.html (Search for '1[2-9]')
Or this, MDN:Plurals