When a person is suddenly left fatally injured from an accident but are conscious and death is imminent, can they usually still think/speak rationally?

Princess Diana was conscious immediately after the car crash, according to the reports. I don’t know if it was to anyone in particular, but she did speak of how much pain she was in before she passed out. Unfortunately, her injuries were severe enough that she didn’t have a chance.

Did you see the video of the death of the Iranian woman? She could not have spoken because her mouth filled with blood. As you said yourself, it depends on the injuries.

People can sometimes feel themselves dying.

After a traumatic injury, there is a chemical numbing that allows for brief lucidity.

Yes, you can see that poor woman going into shock. I think she was shot in the chest.

It is believed that when an individual has its head severed.
They are still aware for a few seconds.

DIg this:
http://www.straightdope.com/columns/read/1172/does-the-head-remain-briefly-conscious-after-decapitation

It depends on the injury. However, generally if they are conscious and collected enough to speak, the injury is considered to be “mortal” rather than “fatal.”

However, a friend had a brain aneurysm burst this week. She could only say “It hurts” before losing consciousness. She never regained consciousness, was flat-lined already by the time the EMTs were there. Her body could be kept alive on machines, but she wasn’t there any longer. She was allowed to die peacefully, without ever uttering another word.