I am reading a book called The Ring of Words, Tolkien and the Oxford English Dictionary by Gilliver, Marshall, and Weiner. I have just finished the first part and was thumbing through the other 2 parts. The 3rd part is called Word Studies. I happened to see the words Eleventy-one and gross, as a title of an entry (pgs112-113). I read it and found it very interesting. We kinda went all over the place with this thread, talking a little bit of the Elven use of the duo-decimal system. But, rather than create another thread (so far), I'll put what I found here, until we find a better home. "But, as always with Tolkien, the roots go deeper, and are planted in the reality of the culture of the ancient world. In Old English,...after hund 'hundred'....if we remove the prefix, we get -endlufontig 'eleventy' and -twelftig 'twelfty'. Why did the Anglo-Saxons count up to 'twelfty'? The answer lies in an ancient system of counting in twelves; much later, at the end of the Middle English period, certain commodities, such as fish, were counted in 'hundreds' that actually contained six score or 120...."
The entry then turns to gross, and how it is used for 12 dozen, and that Hobbits used this term, which was already mentioned in this thread. I will add here though, that an early draft in HoMe VI pg 23, included the phrase, 'engrossing entertainment' during Bilbo's party. But, the pun disappeared in the published version.
The entry returns to 'eleventy' with the Icelandic word ellefu-tui. "...frequent in reckoning by duodecimal hundreds".
Stimulated by the Cuivienyarna posts here -- I'm looking into one aspect of JRRT's writing, his use of "child's tale, mingled with counting-lore." Researching now such base topics as "gnomic rhyming," "wisdom literature," and "teaching verses." Mesopotamian "wisdom texts," classical Greek gnomic literature, and the Nordic texts of Lore will all figure heavily in this attempt to see how JRRT adapted these forms to his own Middle-earth creations.