While at work I have to take a patient's consent in which I explain the plan and the risks to which they may be exposed.
I've given the same speech so often that my brain goes on automatic pilot and I don't even hear myself saying it anymore. In fact, at times I find myself wondering if I actually gave it as it's become so automatic.
I've heard John Oliver describe this phenomenon as mouth noise. (Unfortunately, I cannot find a link to this.) But to paraphrase:
He's said this so often it's just mouth noise to him at this point.
Is there a more formal name for this phenomenon? I'm not looking for by rote or similar. I'm seeking the phenomenon where you don't even notice your own words anymore.
I'd use it in a sentence such as:
I've given this speech so many times it's become .......