Sleep rhythm is controlled by the circadian cycle, which functions as an internal timekeeping device, temperature control, and as part of the body that acts as a transmitter associated with wakefulness. "Sleep duration is also controlled by circadian rhythms; that is, the time you go to sleep influences how long you sleep." (Zimbardo and Richard 143). A consistent pattern of cyclical activities of the body, this cycle constantly working on restoring and maintaining our bodies. “About a third of your circadian rhythm is dedicated to that period of behavioral quiescence called sleep.” (Zimbardo and Richard 141) Sleep proceeds in cycles of rapid eye movement (REM) and non-REM (NREM) sleep, cycling through the former in phases at approximately 90 minute intervals, Phase N 1, Phase N 2, Phase N 3 and N stage 4, all of which are NREM sleep. They last about 10 minutes, then you enter REM sleep, the amount of REM sleep increases later in the sleep cycle. Stage N 1 is sometimes called drowsiness or drowsy sleep, and can be identified by sudden twitching, jerking, and loss of muscle tone. Some experience hallucinations during this phase and have little conscious awareness of the external environment. This stage can be identified on an EEG with the manifestations of theta Stage N 2 can be seen by the muscle activity measured by the EMG decreases and the EEG shows the sleep spindle and k complex. During this phase, conscious 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 of stage N 4. Rapid eye movement sleep, or REM sleep, a rapid sleep low voltage... middle of paper.. ....theories hold that general cognitive processes process language acquisition and that the end result of these processes are language-specific phenomena, such as word learning and the acquisition of grammar. By learning grammar we learn that a phoneme is the smallest part of speech, made up of sound letters, syntax is how to put words together, semantics what the words we are putting together mean and pragmatics are the rules we use when we are a conversation. “A child's first step in acquiring a language is to take note of the sounds that are used significantly in that language.” (Zimbardo and Richard 314) Some language acquisition researchers believe that language acquisition relies primarily on mental structures that facilitate the comprehension and production of language. Children develop a belief about the meaning of words, in the same way that scientists try to develop hypotheses.