Youngfun wrote:Yea, I'm always reluctant to explain 们 as the plural, because for example you don't say 两个孩子们 for "two kids".
To be fair, though, even languages with grammaticalised plurals often use an unmarked form after numbers, e.g. Hungarian két gyerek "two children" (not *két gyerekek). It's more evident from expressions like "五岁或未满五岁的孩子免费入场", since obviously it's not just one child under 5 wholl be allowed in without paying.
Youngfun wrote:More food for though about the etymology of 们：http://forum.wordreference.com/showthread.php?t=2267572&p=11422635#post11422635
That stuff about a "oblique Altaic ending" is nonsense. The polite forms are transparently derived from contraction of -men, e.g. tāmen > tām [still found in some dialects] > tān. And there's nothing "ungrammatical" about "double plurals". You find these frequently in other languages. In fact, children is one such example.