Word frequency effect  The word frequency effect is a psychological phenomenon where recognition times are faster for words seen more frequently than for words seen less frequently. Word frequency depends on individual awareness of the tested language. The phenomenon can be extended to different characters of the word in non-alphabetic languages such as Chinese. A word is considered to be high frequency if the word is commonly used in daily speech, such as the word "the". A word is considered to be low frequency if the word is not commonly used, such as the word "strait". Some languages such as Chinese have multiple levels of daily speech that impact frequency of words. There is frequency at the character level or at the word level. There is also an effect of frequency at the orthographic level. Lower frequency words benefit more from a single repetition than higher frequency words. Most studies looking at the word frequency effect use eye tracking data. When words have a higher frequency, readers fixate on them for shorter amounts of time. In one study, participants' eye movements were recorded as they scanned single sentence stimuli for topic relevant words. Researchers used an Eyelink eye tracker to record the movements of the participants' eyes. Reading times were found to be longer when focusing for comprehension due to increased average fixation durations. Results showed that reading for comprehension rather than scanning for certain words took longer fixations on the text. A second method used to measure the word frequency effect is electroencephalogram (EEG). The results collected using EEG data vary depending on the context of the word. Expected or high frequency words exhibit a reduced N400 response at the beginning of the sentence. This study found that predictable words showed a lower N400 amplitude, but did not find a significant effect of frequency. More research is needed to see how frequency affects EEG data. A third method of measuring the word frequency effect is reaction time. Reaction time is used particularly when reading aloud. Participants pronounce words differing in frequency as fast as they can. Higher frequency words are read faster than the low frequency words. The word frequency effect changes how the brain encodes the information. Readers began spelling the higher frequency words faster than the lower frequency words when spelling the words from dictation. The length of saccade varies depending on the frequency of words and the validity of the previous (preview) word in predicting the target word. For higher frequency target words, the saccades as the reader approaches the word is longer when there is a valid preview word in front of it than for lower frequency words.