I'm just using this as an example here, but it's been around for a while now. Some texts the Siri female voice is not able to speak, and, instead of speaking, causes the device (in this example, my iPhone SE) to respring. Here's a bit of text that can't be read on my device, copied from the list of searched Wikipedia pages in the Wikipedia app:
Summer of Love
Mid 1967 social and political phenomenon in San Francisco, California, USA Actions available
This is raw voiceover text, and in the app, all but the American Siri female can't read. Does anyone know what the problem might be?
Note: this text is just an example, so only take this as an example. I've encountered similar problems when flicking through other apps, but this is the example that came off the top of my head. This is still there in iOS 11.2.