Siri's voice is shaky like an old lady

I have an iPhone 5S running 10.2.1 and I've noticed that Siri is starting to sound like an old lady, actually shaky. Am I the only one hearing this? Not finding any other posts about this anywhere. It isn't happening all the time but definitely happening.

Maybe just age of my phone? Speaker component going out? Which would be funny, Siri's voice aging with your phone!