(By Hedvig Skirgård): "This question concerns regular marking of plural number in the noun phrase by a marker that is not bound to the noun but free-standing. This marker should occur with an open set of nouns, not with a restricted set. This feature contrasts with GB044 Is there a productive morphological plural marker on nouns? which focuses on bound marking of plural number. For more on wordhood and bound marking, please see this page. ❡
Number marking is often fused with marking of other categories, such as definiteness/specificity or gender/noun class. It is possible for the number marker to also signal other functions and still be coded as 1, as long as these other functions do not interfere with the number distinctions and as long as number marking is productive and regular."