Got a few comments with last night's post. One suggesting my proposed system become more complex, another basically wondering why I'd ever change the RAW on alignment languages, the final one sorta suggesting the same thing as Noisms' idea which spawned my own.
Thanks for the comments, though. Even though I'm not looking to make this more complex than I feel is necessary, I appreciate suggestions for improvements, and hope that they make YOUR game better for YOU. For those that like alignment languages as written, great! They are one of the sticky issues for many gamers, and if they don't bother you, that's one less thing to worry about (if you also like Demi-Human level limits, race-as-class, weapons vs. armor charts, psionics, etc. why are you even on the internet discussing D&D? I thought it was for us cranky old coots who always want to bitch and moan and tinker... :D ).
Anyway, my point tonight is to restate my idea in simpler terms.
"Alignment languages" in my game will CEASE to be alignment languages as commonly understood. They will be dead languages within the campaign world: the cultures that spawned the languages have disappeared, and the successor cultures may speak a language based on them, but they are still different languages. People use them for various purposes (religious, mercantile, academic, etc.). Most educated people (and all adventurers) know one or more of them, but rarely use them in everyday life.
The only link to alignment will be that your starting choice of alignment determines which of the languages your character knows. Just like how Demi-Humans gain bonus languages for racial purposes in Old School D&D, these will be just a bonus language characters get. The fact that others of the same alignment will share it makes it useful for the role of RAW alignment language, but as I said, it's not exclusive.
For example, let's say I've set up Latin as the language Lawfuls start with, Ancient Greek as the language Neutrals start with, and Ancient Egyptian as the language Chaotics start with. Bob rolls up Gargamel, a Neutral Magic-User with a 17 Int, entitling him to two bonus languages. He gets French (Common, everyone has it) and Ancient Greek (for being Neutral). He wants to speak to dragons, so he takes Dragon as a bonus. He then decides that communicating with any humanoids he charms would be useful, so he decides that for his second bonus language he will learn Ancient Egyptian.
Now, anyone trying to test Gargamel's alignment will know he's not Lawful, but won't be sure if he's Neutral or Chaotic (if they're using the dead languages as a shibboleth).
Other than that, the languages are just that - dead languages. Sometimes things will be written or spoken in them, and PCs that know that language will benefit. Those that don't will need to rely on translators, magic, or thieves (in the case of written text).
Other than the artificiality of determining which of these languages a PC knows based on alignment, they're just normal languages.
Now, one thing I forgot to mention last night. Third Edition D&D already had something similar to this. Instead of alignment languages, they had the planar languages. Auran, Terran, Ignan, and Aquan were for Elemental Planar dwellers, while Celestial was the language of all Good outsiders, and evil outsiders were split between Infernal (LE) and Abyssal (CE). Don't remember which (what?) NE outsiders spoke.
Anyone could learn Celestial, even if you were the most Chaotic and most Evil of people. Nothing stopped you. Characters in 3E didn't get one of these languages automatically, though, so that's a point of departure. Basically, though, my idea will work something like the 3E planar languages, except they're not the languages of beings from other realms.
Also, for those playing AD&D or other systems with more complex alignment, a simpler solution than coming up with nine dead languages would be simply to have five (or six if you want one for LNC Neutral and GNE Neutral). Lawful, Chaotic, Good, Evil and Neutral each get a language keyed to them. PCs get to choose one, depending on their alignment. If a DM is feeling generous, they can get both.
Hopefully this explains my idea a bit better. If you like it, or at least find some kernel worth modifying for your own games, I'm happy. If you like the rules as written and don't think it needs tinkering with, that's fine. I've used the rules as written (in Mentzer's Basic Set anyway) for years and never had a problem with it. This system, to me at least, seems to offer more oomph for no real great increase in complexity, so I'm gonna at least give it a try and see how it plays.