My three year old daughter cries while asleep periodically but does not shed tears. is that normal? although i have seen her laugh and smile sometimes

Crying: If her crying during sleep is a persistent problem discuss it with your doctor. It is possible that your child may be in pain, having nightmares, or even the possibility of a seizure disorder.

Sleep talking/etc.: Sleep talking/ crying / writhing in bed and similar events can be sleep entry disorders.These are seen more often with kids who have irregular sleep habits, or have short or long term sleep deprivation. A visit with your doc to review the issue can identify any other problems. A change in sleeping routine may improve things, or it may improve over time by itself.