Are You Talking to Me Are You Speaking to Me?

We stress grammar words to contrast information for example if we're contradicting what someone is saying so I said you told me it was on the left no I didn't tell you that. Normally we don't stress words like didn't or can but if we want to contradict what the other person is saying then we're going to emphasize those grammar wordsYeah that's perfectly clear have you seen the film Taxi Driver with Robert De Niro it's a very old film I have a very good one do you remember the bit where he's standing in front of the mirror and he's saying are you talking to me  and he's stressing that me? It's a classic example of a small grammar