i have this exact same problem with my Samsung Galaxy 4. The photo at the top is exactly what I have been dealing with. I've contacted straight talk and they want to reset my phone. I've done a hard reset on it and this problem persists. Its obvious that this is not a defect in my phone as it happened about the same time as everyone else had their problem. I tried to contact Google but they make it seemingly impossible to reach a human. The Straight talk rep I talked with today tried but had no answer, just said they would escalate the problem to a superior and to call back tomorrow on a different phone. I've done the hard reset and they claim to have no record of this problem. - So aggravating, I can't use this at night, its like I have a flashlight on my face every time I use the speech to text option. - Other than shooting this phone and going with a different phone, I don't know what to do. If I get a new Android phone and this happens again, I still have no solution what to do then. I posted this problem on Android Forums and others have the same problem
http://androidforums.com/threads/speech-area-is-now-white.1012356/ so this is a genuine bug that Android/Google hasn't addressed.