Automatic Scaling of Text for Training Second Language Reading Comprehension

For children learning their first language, reading is one of the most effective ways to acquire new vocabulary. Studies link students who read more with larger and more complex vocabularies. For second language learners, there is a substantial barrier to reading. Even the books written for early first language readers assume a base vocabulary of nearly 7000 word families and a nuanced understanding of grammar. This project will look at ways that technology can help second language learners overcome this high barrier to entry, and the effectiveness of learning through reading for adults acquiring a foreign language. Through the implementation of Dokusha, an automatic graded reader generator for Japanese, this project will explore how advancements in natural language processing can be used to automatically simplify text for extensive reading in Japanese as a foreign language. AUTO TEXT SCALING FOR READING COMPREHENSION 5 Introduction Reading is a complex cognitive process that improves with practice and exposure to the correct difficulty level of text, and results in a myriad of benefits to language skills. Because reading is such a natural and integral component of language acquisition, most native speakers of a language advance their lexicon through reading in their native language as soon as they are capable of it. While just as beneficial for foreign language study, reading in a second language is a much more daunting task. To become proficient readers, secondlanguage learners have to work around their linguistic disadvantages. The correct level of text for a native speaker, who has years of acquiring language orally as a solid linguistic foundation for literacy, is not an ideal entry point for the second language learner, who generally studies the written and oral aspects of their target language simultaneously. Still, there is good evidence in the literature that learning to read in a second language can create higher motivation for learning the language (Hitosugi & Day, 2004; Mason & Krashen, 1997; Swaffer & Woodruff, 1978), help learners build a more diverse and rich vocabulary (Horst, 2005; Nation, 2013; Pitts, White & Krashen, 1989), and can be a largely autonomous way to improve language skills (Benson, 2011). In addition to its lexical benefits, reading has been shown to have a positive effect on learner motivation. When the University of Texas changed the focus of their German program in 1975 to deemphasize grammar and in-class language production in favor of learning through input, both verbal and written, they found the percent of students who elected to continue their German studies after the first term jumped from an average of 55% per year to 72% (Swaffer & Woodruff, 1978). The students in these classes were encouraged but not required to speak German during class. From the fifth week of the first term through AUTO TEXT SCALING FOR READING COMPREHENSION 6 the remainder of the program, the focus of the course was primarily on reading comprehension. The students started by reading dialogues and progressed to newspapers by the end of the second semester class. In addition to the lower attrition rates, the students responded positively to the new curriculum in feedback forms, and scored higher than average on a national test conducted by the Modern Language Association. Other researchers have also found that a curriculum structured around reading contributes significantly toward increasing learner motivation (Hitosugi & Day, 2004; Mason & Krashen, 1997). Second language (L2) vocabulary can be acquired through the reading of large amounts of comprehensible text as demonstrated by Saragi, Nation, and Meister (1987). In this study, which examined how vocabulary is acquired from comprehensible context, students were asked to read A Clockwork Orange in their native English. The students were subsequently tested on their understanding of 90 of the Russian slang words that appeared in the book. The average score on the vocabulary test was 76%, with higher scores on a word being correlated with the number of times it appeared in the book. This suggested that given enough exposure to a word in context, the word will be acquired by the reader. This study inspired a number of other studies on L2 vocabulary acquisition through extensive reading of both authentic texts (Horst, Cobb, & Meara, 1998; Pellicer-Sánchez & Schmitt, 2010; Pitts et al., 1989) and graded readers -books written specifically for beginning second language learners (Horst, 2005; Waring & Takaki, 2003). Reading also has a powerful role to play in non-classroom study. One of the appealing points of studying a language through reading is that reading can be a largely autonomous and private way of improving language skills in general. Pickard (1995) AUTO TEXT SCALING FOR READING COMPREHENSION 7 released a case-study following three proficient German students studying English at the University of Humberside. Through interviews and questionnaires, Pickard found that these successful students used a wide array of strategies to advance their language skills outside of the classroom. The students in the study reported that they believed reading newspapers and novels was an extremely important contributing factor to their success at learning English. This study highlights one of the most compelling reasons for language learners to learn to read: it is a largely self-directed activity. While teachers can certainly scaffold and help teach literacy, reading is not dependent on having access to a speaker of the language in the way that conversation and communication based approaches are. This may be why reading is a method that autonomous learners commonly employ when learning a second language (Eskey, 2002; Hyland, 2004; Leung, 2002, Senoo & Yonemoto, 2014). Learning to read in a foreign language strengthens language skills and is enjoyable enough to help learners stay interested and motivated over time. Linguistic benefits aside, reading is also a very accessible activity. It is available as a way to build students’ language comprehension both in and out of the classroom, as well as that of independent learners regardless of their access to native speakers. Texts are available in almost any language online and so, unlike conversation, which requires a speaker to converse with, access to text is easy for most people. Perhaps due to the comparative difficulty of studying independent language learners, there is a dearth of studies on independent learners in general, and most of the studies on the benefits of reading have been conducted on students in classroom settings. Despite this, reading can be used to great effect outside of traditional studies as long as the appropriate text is available (Senoo & Yonemoto, 2014). AUTO TEXT SCALING FOR READING COMPREHENSION 8 Yet finding level-appropriate texts for less popular second languages, such as Japanese, can be incredibly difficult for classroom and independent students alike. Because of this lack of leveled reading resources, students may not have access to enough sufficiently motivating, appropriately-leveled text for reading to be an effective learning tool for them (Hitosugi & Day, 2004). Given the crucial role reading plays in the L2 acquisition process, lack of adequate reading material to meet a student’s needs at their unique level could present a significant obstacle to learning (Day & Bamford, 1998; Elley & Mangubhai, 1983; Krashen, 1985). Here, recent developments in the field of computer science known as natural language processing (NLP) could play a role in solving the problem of creating appropriately-leveled language learner text. If a computer program could be constructed to reduce the level of a piece of text automatically, then it would eliminate the problem of finding a large enough variety of appropriately leveled text for a Japanese extensive reading program. Additionally, independent learners would be able to self-convert text found online to the ideal level for them to read fluently for meaning. It would even be possible for the same text to be scaled to multiple levels, enabling learners to work their way into more complicated language with a solid understanding of the content of the text obtained through initial readings at lower difficulty levels, or for students at different reading levels in a group class to work through the same text at the level most appropriate to their current L2 learning needs. To demonstrate this, the design, implementation, and analysis of the automatic graded text generator Dokusha will be examined. AUTO TEXT SCALING FOR READING COMPREHENSION 9 Children's Literature in the L2 Classroom Making the appropriate level of text available to students is not always an easy task. Extensive reading programs in English classrooms typically give students access to a library of graded readers, texts written at a specific level of language for foreign language learners. This allows students to select books that interest them at their current level. However, graded readers in non-English languages are not as common, and the smaller selection prevents learners from accessing texts that they are motivated to read at the correct difficulty level for them. As a result of this lack of appropriate language learner literature, extensive reading programs in other languages may resort to using children's literature (Hitosugi & Day, 2004). Children’s literature is not an ideal substitute for graded readers. While written for children without the full lexicon of an adult native speaker, children’s literature still assumes a much more complete understanding of vocabulary and an implicit understanding of the complex grammar of the language. Although Day and Bamford (1998) claim that "If a language lacks language learner literature, teachers can turn to a sure source of easy reading material that exists in almost every language: books designed to teach children their first language"