LotR -- Book 1 - Chapter 01 - A Long-Expected Party

[Thinlómien]

...and of course we intentionally started on September 22nd, but apparently we were even more accurate than we thought we would be because Bilbo and Frodo's birthday was Thursday September 22nd, just like today. Nice!

On this reread, the thing that caught my eye the most was the hobbits' conflicted relationship with literacy. It's said - elsewhere - that hobbits tended to learn how to cook before they learnt their letters and many never got so far as the latter. Here Gaffer Gamgee is very defensive about letting his son to learn reading and writing. Yet Bilbo sent written party invitations by a well established mail service and there's no mention of some people not understanding their mail. Furthermore, letter writing seems commonplace.

Is there a subtle class division here? Or is Tolkien poking fun at hobbits and consequently at "common people" for their lack of reading comprehension/ aversion to reading? Or is his world building simply a little incoherent? (The hobbits get the most anachronistic parts too, anyway.) I think I might be one of those instances were Tolkien's otherwise very complete world-building is forgotten in favour of something else - in this case, social commentary.