AVSpeechSynthesizer doesn't work on iOS10

Turn off your silent mode (the physical switch).It works in my case.

I just ran into this same issue on an iPad Mini 4. This version doesnt have a physical switch. But if you open control center (swipe up), there is a Silent button. Turn this off and the issue fixes itself.

In my project, although I was having trouble getting synthesis to produce the first utterance after initialization, I was able to work around that by rearranging code. But I still have dozens of lines of garbage being spewed to the console when AVSpeechSynthesizer is initialized, and when its first utterance is produced. Here is a little sample:

2016-12-27 06:45:08.579510 SpeechBug1226[2155:859123] [MobileAssetError:1] Unable to copy asset attributes2016-12-27 06:45:08.580248 SpeechBug1226[2155:859123] Could not get attribute 'LocalURL': Error Domain=MobileAssetError Code=1 "Unable to copy asset attributes" UserInfo={NSDescription=Unable to copy asset attributes}2016-12-27 06:45:08.585959 SpeechBug1226[2155:859123] 0x174157fa0 Copy matching assets reply: XPC_TYPE_DICTIONARY  <dictionary: 0x174157fa0> { count = 2, transaction: 0, voucher = 0x0, contents ="Assets" => <data: 0x17426c700>: { length = 1237 bytes, contents = 0x62706c6973743030d4010203040506636458247665727369... }"Result" => <int64: 0x174220180>: 0

I reproduced this in a small demo project and was unable to find a workaround. Sadly, I'm afraid that the correct answer to this question is to file a bug, which I just did :(