Final answer:
Sleeptalking is most likely to occur during stage 2 and stage 3 non-REM sleep, with stage 3 being known for deep sleep characterized by low frequency, high amplitude delta waves and a lowered heart rate and respiration.
Step-by-step explanation:
Sleeptalking, also known as somniloquy, can occur during any sleep stage, but it is most likely to happen during stage 2 sleep and non-REM sleep, particularly during stage 3 sleep, which is often referred to as deep sleep or slow-wave sleep. Stage 3 is characterized by low frequency, high amplitude delta waves, making it a time when it is more difficult to awaken someone.
During stage 3, the heart rate and respiration slow dramatically, and the brain produces delta waves. While sleepwalking and sleeptalking can occur at different times, they are typically associated with non-REM sleep, and the deep stages of non-REM sleep are more conducive to these behaviors.