Abstract: Many previous studies have shown that frequency of language input played an important role in second language acquisition. Language learners are very sensitive to the frequencies of items and to co-occurent combinations in language input. High-frequency items are acquired earlier and better than low-frequency ones. Studies on Chinese character recognition also showed that high-frequency characters are recognized more quickly than low-frequency ones. But few studies investigate the frequency effects in Chinese as a second language because the frequency data of characters in a second language is not as easily available as in a first language. In the meanwhile, whether or not the productivity of a character (i.e. the word formation ability of a character) has an effect on character learning is still an unresolved question.
The present experiments investigated the effects of frequency and productivity of characters on character learning by elementary L2 students of Chinese as a second language from alphabetic language backgrounds. In Experiment 1, 55 first-year adult learners of Chinese as a second language from Beijing Language and Culture University were asked to write down the Pinyin and make words or phrases for 100 learned characters which were selected from their textbook and were different in frequency of occurring in the learner’s textbook and stroke number. The percentage of correct number in Pinyin, meaning and that of both correct in Pinyin and meaning were calculated respectively and then were analyzed using ANOVAs. In Experiment 2, 35 participants were asked to write down the Pinyin and make words or phrases for 64 learned characters which were selected from their textbook and were different in numbers of word formation.
The results showed that the high-frequency characters were learned better than the low frequency ones and this effect was larger for characters with more strokes than that with fewer strokes. But the effect of productivity for characters to forming words on subjects’ performance was not significant.
These results suggest that input frequency is an important factor during the acquisition of Chinese as a second language. The frequency effects in second language acquisition could be explained within the theory of implicit learning, which claims that acquisition of knowledge is a process that takes place naturally without conscious operations. The lack of significant effect of productivity may be because the productivity would have no effect on the learning of high frequency characters, which were used as stimuli in Experiment 2, but it would not be the case for low frequency ones. Therefore, further research on the productivity of character is needed in the future

Key words: frequency effect, frequency of characters, productivity of characters, character learning, teaching Chinese as a second language