terminal command say produces error The "say" command in OSX Terminal works fine for me and I use it now end then.
However, since last week it produces the following error message on my Mac Mini (Late 2012, 10.8.4):

$ say test
&gt; MTBEAudioUnitSoundOutput::PropagateProperty Error -10851
&gt; MTBEAudioUnitSoundOutput::PropagateProperty Error -10851


The sound is produced as expected, so no big drama, but I'd like to know if somebody else suffers from the same problem or if that error has something to do with my specific setup here... and, of course, what this message means.
A little Googling suggests that  it's a new problem in 10.8.4. A couple people in this MacRumors forum thread have experienced the same, as has the author of this blog post. No indications as to how to get rid of it however.

I haven't seen any error when testing say, so it may be some combination of hardware that causes it, but if the sound output is as expected, I wouldn't worry too much about it, and it will probably be fixed eventually.

If you're using say in shell scripts and need the Terminal output cleaned up a bit, you could always pipe it through grep: say test | grep -v "MTBEAudioUnitSoundOutput::PropagateProperty Error -10851".