The rhythm of sleep is controlled by the circadian cycle, functioning as an internal timing device, temperature control and by the part of the body which acts as a transmitter associated with sleep awakening. “Sleep duration is also controlled by circadian rhythms; that is, the time at which one falls asleep influences sleep duration.” (Zimbardo and Richard 143). A consistent pattern of cyclical bodily activities, this cycle constantly works to restore and maintain our body. “About a third of your circadian rhythm is devoted to this period of behavioral quiescence called sleep.” (Zimbardo and Richard 141) Sleep occurs in cycles of rapid eye movement (REM) and non-rapid eye movement (NREM) sleep, passing through the first stage at intervals of approximately 90 minutes, stage N 1, stage N 2, stage N. 3 and stage N 4, which are all NREM sleep. Lasting about 10 minutes, you then enter REM sleep. The amount of REM sleep increases later in the sleep cycle. Stage N 1 is sometimes called drowsiness or drowsy sleep. , can be identified by sudden contractions, jerking and loss of muscle tone. Some experience hallucinations during this stage and have little awareness of the external environment. This stage can be identified on an EEG with displays of stage N 2. can be observed by the decrease in muscle activity measured by EMG and EEG displaying the sleep spindle and k-complex. During this stage, awareness of the environment disappears, occupying 45-55% of total sleep in adults. Stage N 3 can be filled with parasomnias. night terrors and sleepwalking, this stage can be seen on an EEG, the delta waves will be slightly smaller than those in stage N 4. Rapid eye movement sleep, or rapid low-voltage REM sleep...... middle of paper .. ....theories hold that general cognitive processes of language acquisition and the end result of these processes are language-specific phenomena, such as word learning and grammar acquisition. In learning grammar we learn that a phoneme is the smallest part of speech, the sound of letters, syntax is how we put words together, semantics is what the words we put together mean and pragmatics are the rules we use when we are in a conversation. . “A child's first step in acquiring a language is to take note of the sounds used meaningfully in that language.” (Zimbardo and Richard 314) Some language acquisition researchers believe that language acquisition relies primarily on mental structures that facilitate language comprehension and production. Children develop a belief about the meaning of words, in the same way that scientists attempt to develop hypotheses..