Since I found this poll through the news page, a fair bit of what more I wanted to know was in the first post.
I'd hope for a lot of rules options, or better yet, game sub-systems and structures for world-building, out of this work. I'd like to see game applications as half of the table of contents, rather than just the last line. To be frank, of the three ingredients of crunch, cream and waffle, there's not much cream in this concept and you don't need most of your confection to be waffle.
Do you have an idea yet of how you want to change Speak Language, how it incorporates all of those good things that you mentioned in your first post, and how not to make it invalidate the skill choices that players and supplement writers have already made? How many skill points and feats do you think a player will want to spend on languages?
One thing that would be really useful to me, not specifically for d20, is a simplified but complete or even speculative family tree of real Earth language families, their taxonomy (if those are the terms I want) and major languages in each. It needs to be a fruitful game source and an engaging read in itself, both of which are far removed from the aims of a textbook: not a bad general description of my hopes for this project, in fact.
Please let me cast a vote not to include any sample languages. As someone else pointed out, you don't have room, and to me, someone else's con-lang is of interest almost solely to the creator, until it's applied in story to describe concepts that are interesting in their own right. I include Tolkien in that.
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