As the title says, almost all NPCs are now Randy. I googled the issue and in my registry SIMS_LANGUAGE and LANGUAGE are set to 'USEnglish' and '409' respectfully.

Elsewhere there's a thread linked and a post mentions another value, SIMS_OTHERLANGUAGE but I don't see that.

Anyone have any idea what's up and what I can do to fix this easily?

Sounds like your UserData is corrupted. If you have an earlier backup of it, try restoring that by moving out the current UserData folder, and replacing it with the older one.

Changing the registry key entries (changing the language) after you have started a new game and the neighbourhood has been created can result in such a corruption. (As well as editing NPCs, townies, and player sims outside the game.)

Funny thing, I'm playing from a back up. I reinstalled my game on a new PC and inserted the userdata from the original computer. I suppose I could completely start over but that'd be a drag.

If you changed the game's language after you've created a neighbourhood, then I'm afraid you'll have to start over to be sure that everything's going to work fine.

If you've backed up your game, you could try emptying the UserData/Characters folder (that's where all the player characters and NPCs are saved), but that would be almost like starting over (except you'd get to keep the houses). No guarantee that things won't fall apart and be completely corrupted in UserData.

You could also try manually renaming the characters/NPCs yourself, using IFF Pencil 2.

But I think by far the most sensible thing to do is to start over if you've changed your game's language. And by starting over, I mean I would actually reinstall the whole game from scratch.

The game's not designed for on-the-fly language and other installation setup changes. It's actually very sensitive to such changes. You can make such changes before you launch the game for the first time -- not after.

I never changed the game's language. Moving to a new PC, I reinstalled the game, then moved in my back up userdata, downloads etc. I solved the issue by using simenhancer to delete all the affected Sims/pets and someone had uploaded the US name database so I put that file in my game and so far, so good. The Game generated new NPCs and they all have different names.

Are you sure it was installed in the same language though? The game will install to the language your OS is set to, so if your old PC was UK English and the new one US English for example, that would have the same effect.

Both data nodes in the registry were 'USEnglish'

It's possible that you used different region discs to install the game the first time around than you used to install it now. That's the only other thing I can think of that would cause this.

For future reference, when backing up the game, you can back up the entire Sims folder (the whole game), as well as the registry entries by exporting them. Then, on the new computer, you just copy the Sims folder to the same location, and import the registry entries, and the game will continue to work, continuing on from where it left off.

Once you've installed the game, you don't really need to re-install it again, so long as you keep a backup of the whole game (installation folder, plus Electronic Arts and Maxis registry entries).