One of the most needed resources for developing open response conversational CALL applications is large corpora of non-native transcribed speech data, of both read and conversational speech. Since accents vary depending on the student's first language, separate databases must either be collected for each L1 subgroup, or a representative sample of speakers of different languages must be included in the database. Creating such databases is extremely labor and cost intensive--a phone level transcription of spontaneous conversational data can cost up to one dollar per phone. A number of multilingual conversational databases of telephone speech are publicly available through the Linguistic Data Consortium (LDC), including Switchboard (US English) and CALLHOME (English, Japanese, Spanish, Chinese, Arabic, German). Our own effort in collaboration with John Hopkins University (Byrne, Knodt, Khudanpur, & Bernstein, 1998; Knodt, Bernstein, & Todic,1998) has been to collect and model spontaneous English conversations between Hispanic natives. All of these efforts will improve our understanding of the disfluent speech of language learners and help model this speech type for the purpose of human-machine communication.
DEFINING AND ACQUIRING LITERACY IN THE AGE OF INFORMATION
Moll defined literacy as "a particular way of using language for a variety of purposes, as a sociocultural practice with intellectual significance" (1994, p. 201). While traditional definitions of literacy have focused on reading and writing, the definition of literacy today is more complex. The process of becoming literate today involves more than learning how to use language effectively; rather, the process amplifies and changes both the cognitive and the linguistic functioning of the individual in society. One who is literate knows how to gather, analyze, and use information resources to solve problems and make decisions, as well as how to learn both independently and cooperatively. Ultimately literate individuals possess a range of skills that enable them to participate fully in all aspects of modern society, from the workforce to the family to the academic community. Indeed, the development of literacy is "a dynamic and ongoing process of perpetual transformation" (Neilsen, 1989, p. 5), whose evolution is influenced by a person's interests, cultures, and experiences. Researchers have viewed literacy as a multifaceted concept for a number of years (Johns, 1997). However, succeeding in a digital, information-oriented society demands multiliteracies, that is, competence in an even more diverse set of functional, academic, critical, and electronic skills.
To be considered multiliterate, students today must acquire a battery of skills that will enable them to take advantage of the diverse modes of communication made possible by new technologies and to participate in global learning communities. Although becoming multiliterate is not an easy task for any student, it is especially difficult for ESL students operating in a second language. In their attempts to become multiliterate, ESL students must acquire linguistic competence in a new language and at the same time develop the cognitive and sociocultural skills necessary to gain access into the social, academic, and workforce environments of the 21st century. They must become functionally literate, able to speak, understand, read, and write English, as well as use English to acquire, articulate and expand their knowledge. They must also become academically literate, able to read and understand interdisciplinary texts, analyze and respond to those texts through various modes of written and oral discourse, and expand their knowledge through sustained and focused research. Further, they must become critically literate, defined here as the ability to evaluate the validity and reliability of informational sources so that they may draw appropriate conclusions from their research efforts. Finally, in our digital age of information, students must become electronically literate, able "to select and use electronic tools for communication, construction, research, and autonomous learning" (Shetzer, 1998).
Helping students develop the range of literacies they need to enter and succeed at various levels of the academic hierarchy and subsequently in the workforce requires a pedagogy that facilitates and hastens linguistic proficiency development, familiarizes students with the requirements and conventions of academic discourse, and supports the use of critical thinking and higher order cognitive processes. A large body of research conducted over the past decade (see, e.g., Benesch, 1988; Brinton, Snow, & Wesche, 1989; Crandall, 1993; Kasper, 1997a, 2000a; Pally, 2000; Snow & Brinton, 1997) has shown that content-based instruction (CBI) is highly effective in helping ESL students develop the literacies they need to be successful in academic and workforce environments.
CONTENT-BASED INSTRUCTION AND LITERACY DEVELOPMENT
CBI develops linguistic competence and functional literacy by exposing ESL learners to interdisciplinary input that consists of both "everyday" communicative and academic language (Cummins, 1981; Mohan, 1990; Spanos, 1989) and that contains a wide range of vocabulary, forms, registers, and pragmatic functions (Snow, Met, & Genesee, 1989; Zuengler & Brinton, 1997). Because content-based pedagogy encourages students to use English to gather, synthesize, evaluate, and articulate interdisciplinary information and knowledge (Pally, 1997), it also allows them to hone academic and critical literacy skills as they practice appropriate patterns of academic discourse (Kasper, 2000b) and become familiar with sociolinguistic conventions relating to audience and purpose (Soter, 1990).
The theoretical foundations supporting a content-based model of ESL instruction derive from cognitive learning theory and second language acquisition (SLA) research. Cognitive learning theory posits that in the process of acquiring literacy skills, students progress through a series of three stages, the cognitive, the associative, and the autonomous (Anderson, 1983a). Progression through these stages is facilitated by scaffolding, which involves providing extensive instructional support during the initial stages of learning and gradually removing this support as students become more proficient at the task (Chamot & O'Malley, 1994). Second language acquisition (SLA) research emphasizes that literacy development can be facilitated by providing multiple opportunities for learners to interact in communicative contexts with authentic, linguistically challenging materials that are relevant to their personal and educational goals (see, e.g., Brinton, et al., 1989; Kasper, 2000a; Krashen, 1982; Snow & Brinton, 1997; Snow, et al., 1989).
In a 1996 paper published in The Harvard Educational Review, The New London Group (NLG) advocated developing multiliteracies through a pedagogy that involves a complex interaction of four factors which they called Situated Practice, Overt Instruction, Critical Framing, and Transformed Practice. According to the NLG, becoming multiliterate requires critical engagement in relevant tasks, interaction with diverse forms of communication made possible by electronic technologies, and participation in collaborative learning contexts. Warschauer (1999) concurred and stated that a pedagogy of critical inquiry and problem solving that provides the context for "authentic and collaborative projects and analyses" (p. 16) that support and are supported by the use of electronic technologies is necessary for ESL students to acquire the linguistic, social, and technological competencies key to literacy in a digital world.
According to a 1995 report published by the United States Department of Education, "technology is an important enabler for classes organized around complex, authentic tasks" and when "used in support of challenging projects, [technology] can contribute to students' sense ... that they are using real tools for real purposes." Technology use increases students' motivation as it promotes their active engagement with language and content through authentic, challenging tasks that are interdisciplinary in nature (McGrath, 1998). Technology use also encourages students to spend more time on task. As they search for information in a hyperlinked environment, ESL students benefit from increased opportunities to process linguistic and content information. Used as a tool for learning, technology supports a level of task authenticity and complexity that fits well with the interdisciplinary work inherent in content-based instruction and that promotes the acquisition of multiliteracies.
THEORY INTO PRACTICE
These research findings suggest that in our efforts to prepare ESL students for the challenges of the academic and workforce environments of the 21st century, we should adopt a pedagogical model that incorporates information technology as an integral component and that specifically targets the development of the range of literacies deemed necessary for success in a digital, information-oriented society. This paper describes a content-based pedagogy, which I call focus discipline research (Kasper, 1998a), and presents the results of a classroom study conducted to measure the effects of focus discipline research on the development of ESL students' literacy skills.
As described here, focus discipline research puts theory into practice as it incorporates the principles of cognitive learning theory, SLA research, and the four components of the NLG's (1996) pedagogy of multiliteracies. Through pedagogical activities that provide the context for situated practice, overt instruction, critical framing, and transformed practice, focus discipline research promotes ESL students' choice of and responsibility for course content, engages them in extended practice with linguistic structures and interdisciplinary material, and encourages them to become "content experts" in a subject of their own choosing.
CONCLUSION
It can be seen that it is difficult and probably undesirable to attempt to determine the difficulty of a listening and viewing task in any absolute terms. By considering the three aspects that affect the level of difficulty, namely text, task, and context features, it is possible to identify those characteristics of tasks that can be manipulated. Having identified the variable characteristics of tasks in developing the model, it is necessary to look to the dynamic interaction among, tasks, texts, and the computer-based environment.
Task design and text selection in this model also incorporate the identification and consideration of context. Teachers can make provision for their influence on learner perception of difficulty by providing texts and tasks that range across these levels, and by ensuring that learners with lower language proficiency can ease themselves gradually into the more contextually difficult tasks. This can be achieved by reducing the level of difficulty of other parameters such as text or task difficulty, or by minimizing other aspects of contextual difficulty. Thus, for example, learners of lower proficiency who are exposed for the first time to a task based on a broadcast announcement would be provided with appropriate visual support in the form of graphics or video to reduce textual difficulty. The task type would also be kept to a low level of cognitive demand (Hoven, 1991, 1997a, 1997b).
In a CELL environment, this identification of parameters of difficulty enables task designers to develop and modify tasks on the basis of clear language pedagogy that is both learner-centred and cognitively sound. Learners are provided with the necessary information on text, task, and context to make informed choices, and are given opportunities to implement their decisions. Teachers are therefore creating a CELL environment that facilitates and encourages exploration of, and experimentation with, the choices available. Within this model, learners are then able to adjust their own learning paths through the texts and tasks, and can do this at their own pace and at their individual points of readiness. In sociocultural terms, the model provides learners with a guiding framework or community of practice within which to develop through their individual Zones of Proximal Development. The model provides them with the tools to mediate meaning in the form of software incorporating information, feedback, and appropriate help systems.
By taking account of learners' needs and making provision for learner choice in this way, one of the major advantages of using computers in language learning--their capacity to allow learners to work at their own pace and in their own time--can be more fully exploited. It then becomes our task as researchers to evaluate, with learners' assistance, the effectiveness of environments such as these in improving the their listening and viewing comprehension as well as their approaches to learning in these environments.
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