So, out of the box, my S3 S-voice functionality worked pretty well, and I couldn't understand why everyone else had such a problem. And then after a hard reset (started by Sprint tech) I started to experience the s-voice drama everyone else did. Couldn't recognize the difference between 'sh' sounds and 'k', and made up some very entertaining phrases. But, I got it back to working flawlessly with my contacts (even foreign names) and doing all the functions it's supposed to do. And, honestly, it works much better than Siri ever did (converted Mac fanboy). It's important you do this procedure in exactly these steps.
1. Make sure your contacts are backed up in your Google account, and clean up all the duplicates etc.
2. Sync your Google account.
3. If you're in a , leave your network selection as CDMA/LTE, BUT if you're not in a 4G area yet, choose the CDMA (3G) network only. It appears that the network connection is very important for the s-voice understanding you, because it's trying to decipher what you're saying on the fly. It's not a hard coded app in the phone itself, so forcing it to stay on one network will stop it from flipping back and forth in the middle of processing your commands.
3. Factory reset the phone (it should stay on the CDMA-only network, if not, choose it, and it'll reboot).
4. DO NOT sign in with your Google or Samsung acct. Just let the phone boot up all the way and finish without adding any accounts, no matter how many times it asks you to.
5. Boot up S-Voice, agreeing to all the terms, etc. Then go through the S Voice intro, and leave the speak to wake up function active.
6. Now sign in with your Google account, let it completely sync.
7. Do NOT add a Samsung Acct. (This seems to confuse the search function)
8. Update all pre-loaded apps in the Google Play store (gmail, etc.) because it appears to update Google Voice Search, too, even though it isn't listed.
9. Make sure you leave factory settings on voice recognition, language etc. Don't change to UK English or anything else. Do not change to Vlingo by Samsung either.
10. Next, turn off the Wake up with Voice Command.
Your S-Voice should be much more functional now, and understand your voice much better. In fact, you'll notice the voice sounds different than it did before. And try speaking naturally. I found the more you tried to pretend it was a mildly ed relative, the worse it got.
It apparently learns a bit, too. So, after telling it which person/function you're trying to accomplish and it requires a confirm selection, it learns. So, if you get it working, DO NOT clear data or you'll be back to square one. Also, if you do a hard reset/factory reset, do this all over again.
My Svoice works pretty much flawless. It's also synced to my samsung account and using samsung powered by vlingo. I do not use wake up with voice command nor is it on.
The only problem I have is with caller ID announcment. It worked flawless then all of a sudden, it has stopped announcing some, not all, of my contacts by name and just announces thier number. Really weird and I can't seem to fix it....I guess a reset is in order....again.
settings------>accounts and sync------>tap google------>find and tap sync contacts.
Go into contacts----->select menu------>tap merge with google.
Now your existing and all new contacts will sync with google. Bear in mind though, google for some reason is stupid when it comes to saving contact pictures as it resizes them to a smaller resolution making them look hideous on your phone if you ever have to re-install them. I just save all my contact pics to a folder on my SD card so when I re-install (re-sync) I just go back and attach the pics in my folder to my contacts so they are high res again.