It is reasonable to assume that if a person has no exposure to a certain language, that person will not learn¹ that language. Hence, it is widely accepted that the availability of target language (TL) input is one of the necessary ingredients for acquisition of a language. Accepting that general statement as an underlying premise opens the door to one area of research in the field of second language acquisition (SLA), one which focuses on the input which is available to the learner. A starting point for this inquiry is recognizing that although target language input is clearly essential, it may not be sufficient in itself. Allwright (1980) illustrates this point when he suggests that "one would not, as a beginner, expect to learn very much of a language merely from listening to monologues on the radio" (p. 166). Thus the investigation into how humans learn a second language from the available input begins.

In early work in this area, Corder pointed out the distinction between the mere availability of input and "what goes in," referring to the latter as "intake" (1967, p. 23). In order to illustrate this distinction, consider the following lyrics as written spontaneously by a 6-year-old student:

My country disobi
Sweet land o' liberty
o v i c. land where my
father starts land were
the buildrum sprites
over the mountain-
sides let freedom bring.

In order to investigate how learners go about learning a second language (L2), Wagner-Gough and Hatch steered many researchers toward analyzing learners' conversational interactions when they put forth that "we should not neglect the relationship between language and communication if we are looking for explanations for the learning process" (1975, p. 307). One of the researchers who answered this call was Long (1981) whose work suggested that the interactional modifications made by native speakers (NS) during conversations with non-native speakers (NNS) were a major facilitator in successful SLA. This contention propagated a derivative of the Input Hypothesis which Ellis (1990) refers to as the Interaction Hypothesis. Long (1981) first proposed a strong version of the hypothesis which predicted that interactional adjustments are not only necessary for SLA, but sufficient to guarantee acquisition. In light of continued research in this area, Long later adjusts to a weak version of the hypothesis, stating that "linguistic/conversational adjustments are necessary for SLA" (Long 1983a, p. 191).

Allwright (1984b) also put forth two versions of an interaction hypothesis. The first claims that the processes of classroom interaction determine what learning opportunities become available to the learner, and the stronger version suggests that the process of classroom interaction is actually the learning process itself.

Much of the recent research which has investigated NS-NNS interaction has been done by Pica and her colleagues. In a review of her own work, Pica (1992) explains that:

What has been lacking from claims about the necessity for L2 input comprehension ... is a theoretical link between learners' comprehension of L2 input and its incorporation into their interlanguage system, retention in memory, and retrieval during subsequent communication. (p. 201)

In an attempt to investigate this link, Pica, like other researchers, focused on "negotiation" which she defines as:

those interactions in which learners and their interlocutors adjust their speech phonologically, lexically, and morphosyntactically to resolve difficulties in mutual understanding which impede the course of their communication. (1992, p. 200)

The present study tests this theoretical link by building on the research done in this area. Specifically, this study is an outgrowth of research by Pica, Young, and Doughty (1987) which concluded that interactionally modified input played a critical role in comprehension, and a subsequent study, Pica (1991a), which concluded that learners were versatile enough to react to and comprehend L2 input whether they engaged in negotiation directly, or observed negotiation.

The importance of the present study is its investigation of acquisition. With a pretest-posttest design, the present study identifies lexical items unknown to the subjects, embeds these words into the teacher's instructions in classroom communication tasks and measures acquisition of these words. To the best of the author's knowledge, no other studies to date have investigated these variables with young L2 learners; therefore, the present study represents an initial investigation into this area of research. Also of interest is an analysis of the classroom interaction which describes the negotiation for the meanings of these unknown words.

It has been suggested that lexical acquisition can take place by following two different paths, direct and indirect vocabulary learning (Nation, 1982), described as follows:

In direct vocabulary learning the learners do exercises and activities that focus their attention on vocabulary. ... In indirect vocabulary learning the learners' attention is focused on some other feature, usually the message that is conveyed by a speaker or writer. (p. 2)

The communicative approach to language teaching will always be incomplete as long as it only principally considers the communicative act performed by syntax; the interactive management of talk, the signaling, segmentation and feeding back of messages involves lexical as well as grammatical skills. (p. 198-199)

The time has come for research which investigates the relationships among input/interaction, comprehension, and acquisition, as pointed out by Ellis (1990) who, in evaluating the interaction hypothesis, offers the following assessment:
 

It is now a decade since the hypothesis was originally formulated and yet there is still no direct evidence to link interaction to acquisition and precious little to demonstrate that it promotes comprehension. (p. 16)
  Statement of the Problem

With respect to interaction, there is a limited but growing body of evidence showing that interaction can facilitate comprehension. However, whether or not the comprehension brought about through interaction actually results in acquisition is a separate question which remains unanswered. With respect to lexical acquisition, although there are a number of studies which have shown that indirect vocabulary learning occurs through extensive reading (see e.g., Nation & Coady, 1988), our understanding of indirect vocabulary learning through listening is very limited.

The present study brings these two areas together in a quantitative and qualitative analysis of the degree of learners' comprehension and acquisition of new lexical items which have been embedded into communication tasks serving as the basis for teacher-student interaction.
 

 The present study investigates the relationships among interaction, comprehension, and acquisition of new lexical items by young English as a second language (ESL) learners.

 If it is true that negotiation "offers researchers a window on the acquisition process" (Pica, 1992, p. 227), the present study peeks through this window to investigate four general research questions as follows:

1. What is the relationship between interaction and the comprehension of input containing new lexical items?

2. What is the relationship between interaction and the acquisition of these new lexical items?

3. What is the effect of the comprehension of input containing new lexical items on the acquisition of these new lexical items?

4. During group interaction, do the relationships among interaction, comprehension, and acquisition differ for those subjects who orally participate in the interaction as compared to those subjects who are exposed to the interaction but choose not to orally participate?
 

The Theoretical Link

In a discussion of the relationship between input and L2 learning as mediated through comprehension processes, Færch and Kasper contend that if certain pre-conditions are met, it may be possible for learning to take place as a by-product of communication, as they explain with the following assessment:

If input is to function as intake to the learning of higher-level L2 material, learners need to experience comprehension problems; such problems have to be perceived as deficits in their knowledge structure, not in the input; finally, these gaps need to be considered the responsibility of the learner herself and not of the interlocutor. (1986, p. 270)

In a discussion of how L2 input should be conceived of in the light of the different notions of comprehension and acquisition, Sharwood Smith (1986) contends that the essential process of acquisition begins when a learner has to interpret incoming messages in the L2. According to Sharwood Smith, where the focus is communication, the first L2-based mechanisms the learner is going to develop will presumably be ones that will enable him or her to identify content words. Sharwood Smith explains that "the communicative value of content words will probably lead the learner straight-away to make inferences about L2 lexis and begin the process of acquiring L2 competence" (1986, p. 246). Sharwood Smith presents a model of input processing which happens in the interest of acquisition when the learner matches the surface structure of the input with the total meaning representation of the situation at hand. In this model the learner notes any discrepancies then adjusts and restructures the current competence.

In the present study, the learners are provided with input which contains unknown content words which may activate the language acquisition mechanisms described by Sharwood Smith. Since these words are not part of the learners current linguistic knowledge, it is critical to employ these mechanisms to handle their meanings.
 

The present study may provide empirical evidence to shed light on the theoretical link between interaction and learning which has been proposed by Pica (1992). For the present study to support this link, it is necessary for the data to show that comprehension of input containing new lexical items can be brought about through interaction, and that increased comprehension can result in the acquisition of these lexical items as measured by results of the posttest.

For the present study to support the interaction hypothesis as originally stated (Long, 1981) and revised (Long, 1983a), it is necessary for those subjects who initiate more interaction during the information-gap tasks to achieve higher scores in the measure of comprehension and greater gains in lexical acquisition than those subjects who initiate less interaction. Though there is currently some evidence that interaction fosters comprehension, there is still no evidence that this increased comprehension results in increased acquisition. The present study explores new territory by investigating acquisition through the incorporation of a pretest-posttest design which measures growth in knowledge of new lexical items introduced to students during classroom interaction in communication tasks which make up the treatment phase of the study. The use of group communication tasks, in addition to individual tasks, may provide additional evidence for Pica's contention (1991a) that comprehension may result from exposure to interaction as well as from active participation in interaction.
 

As the present study is limited in scope, educational practitioners should use caution in applying the findings to educational practice. The study offers a detailed description of the data; however, due to the small number of subjects, their particular learning environment, and the specific nature of the research questions, the analysis is meant to shed light on the issues involved. Pedagogic suggestions resulting from this study will need to be tested through the day-by-day experiences offered by classroom practice and continued research.