Why do people talk in their sleep?

Question

My mom does it all the time. I think its halarious.

Answer 1

When I talk out loud in my dreams ; its  because I am under lots of stress

Answer 2

I got this from a random website lol:

Sleep-talking actual (scientific) name is "Somniloquy". It is caused by temporary arousals (or peeks) during the NREM and REM phases of sleep, which stands for Rapid Eyes Movement. This is the phase when we have dreams, and the neuron activity is quite similar to the activity registered during the time we are awake.

So basically some people's brain (actually 5% of adults, and 50% of children) "confuse" the REM with being AWAKE and talk in their sleep actually vocalizing out loud what they are saying in their dreams.

Somniloquy has neither side effects nor generate health problems. The most common issue with sleep-talkers is that they awake their partners or other residents of the same house, which is also caused by people that snores loudly.

Somniloquy in some people is unintelligible and in others is very clear. Not all people that talk sleeping are Somniloquers, as people without it can talk sleeping from time to time, usually when they have nightmares or suffer from night-terrors. In these cases more than talking is screaming.