Languages are my guilty pleasure. I have studied Latin, Italian, and Tolkien's invented languages in depth, devoted perhaps too much to Anglo-Saxon, and dabbled a very little bit in German, French, Old Icelandic (Old Norse) and Welsh.
The following links are to posts I've written as well as to amazing sites and articles by people who actually know what they're talking about.
Language Inverted - language is to music as music is to language
Silence - music shouldn't be talked about
This Side of the Pond - American and British English
Vengeful Reading - reading about writing
Wordsmithing - what's a quenarth?
Writing With Annie Dillard - advice from Samuel Johnson
Ardalambion - Helge Fauskanger's Tolkien languages site
Editrix - clever and helpful insights to English grammar
Glǽmscrafu: Tolkien's Linguistic Cellar - a goldmine of Tolkien linguistics
"A poet is a professional maker of verbal objects."
W. H. Auden
"He ate and drank the precious Words,
his Spirit grew robust;
He knew no more that he was poor,
nor that his frame was Dust."