A Self-Organizing Connectionist Model of Character Acquisition in Chinese

Abstract

A Self-Organizing Connectionist Model of Character Acquisition in Chinese Hongbing Xing (xinghb@blcu.edu.cn) Center for Studies of Chinese as a Second Language Beijing Language and Culture University Beijing, 100083, China Hua Shu (shuh@bnu.edu.cn) Department of Psychology, Beijing Normal University Beijing, 100875, China Ping Li (pli@richmond.edu) Department of Psychology, University of Richmond Richmond, VA 23713, USA Abstract Despite growing interests in the acquisition of Chinese orthography, few studies have modeled the acquisition process using connectionist networks. This study uses a self-organizing connectionist model to simulate children’s learning of Chinese characters. There are two major goals of our study: (1) To evaluate the degree to which connectionist models can inform us of the complex structural and processing properties of the Chinese orthography. One of the most difficult tasks in achieving this goal is how to faithfully capture the orthographic similarities of Chinese characters. We derived our character representations on the basis of analyzing a large-scale character database that can be readily mapped to school children’s orthographic acquisition. (2) To test the utility of self-organizing neural networks in orthographic acquisition. Most previous connectionist models of orthographic processing have relied on the use of feed-forward networks. Results from our simulations present positive evidence for both of our goals. In particular, we show that our model demonstrates early regularity effects and frequency effects in the acquisition of Chinese characters, matching up with acquisition patterns from empirical research. Introduction In recent years there have been growing interests in the psycholinguistic study of orthographic acquisition in Chinese (see Yang & Peng, 1997; Shu & Anderson, 1998; Shu, Anderson, & Wu, 2000). A unique feature of the Chinese orthography is that it uses characters rather than alphabetic letters as the basic writing unit, in square configurations that map mostly onto meaningful morphemes rather than spoken phonemes. Processing or acquisition within this “fractal” organization of characters may differ in important ways from that of English and other alphabetic languages (Shu & Anderson, 1998). There are four major types of Chinese characters: pictographic, referential, associative compounds, and ideophonetic compounds. The last type, also known as the semantic-phonetic compounds or, simply, phonetic compounds, is the most interesting and important. In the Dictionary of Modern Chinese Frequent Characters (National Language Commission, 1988), there are 5,631 ideophonetic characters, accounting for 81% of the total 7,000 frequent characters in the dictionary (Li & Kang, 1993). Shu, Chen, Anderson, Wu, and Xuan (in press) collected 2,570 characters listed in the Elementary School Textbooks used in Beijing to establish the “School Chinese Corpus”. They categorized and labeled every character in this corpus, on dimensions such as phonetic part, phonetic type, position of the phonetic part in the character, age at which the character is taught, and frequency of the character. Shu et al.’s analyses reveal that most of the Chinese characters taught in elementary schools are ideophonetics, as shown in Table 1. Table 1 Ratios of ideophonetics in each grade (Shu, Chen, Anderson, Wu, & Xuan, in press) Grade Ratio Mean Given the prominence of ideophonetics in Chinese orthography, it is thus important for us to understand the functions of these characters. Ideophonetics consist of two major components: the semantic part (often called a radical) that gives information about the character’s meaning, and the phonetic part that gives partial information about the whole character’s pronunciation. We say “partial”, because the phonetic radical may or may not indicate the true pronunciation of the whole character, in one of three ways: (a) Regular: the whole character is pronounced the same as the phonetic radical in isolation – that is, the same as the phonetic radical when it is being used as a simple character; for example, “ /qing1/ and “ /qing1/”. (b) Semi-regular: the whole character is pronounced partly as the phonetic radical, with a different