Detail #129: A Distinction in a Number System

Imagine a language that for relatively small numbers ­– say two to a dozen or so – distinguish 'natural group' and 'arbitrary group'. (I will distinguish these as NG and AG in glosses.)

five-NG brothers: five brothers (they have the same mother

five-AG brothers: five persons who all are males and have brothers

ten-NG sailors: ten sailors of the same crew

ten-AG sailors: ten sailors in general