【Abstract】This paper discusses the previous and current research including different hypotheses or models towards incidental vocabulary acquisition and English reading， revealing some factors affecting incidental vocabulary acquisition in English reading process for native Chinese learners， and finally clarifies some strategies on incidental vocabulary acquisition through English reading.

【Key words】second language acquisition； incidental vocabulary acquisition； English reading process

Introduction

In the past decades， a great deal of research has claimed that vocabulary is a key aspect for second language learners to acquire their language skills， including reading， writing， listening， and speaking. According to Nation （2003）， there were two kinds of vocabulary learning： direct and indirect lexical learning. In direct vocabulary learning， learners focus their attention on vocabulary knowledge when they do lexical exercises by applying memorizing techniques， whereas indirect vocabulary learning refers to the acquiring L2 lexical knowledge while learners goal is to draw attention to some other features other than lexical learning. Indirect vocabulary learning is also can be called “intentional” lexical learning. Hatch and Brown （2001） defined intentional learning as “being designed， planned for， or intended for a teacher or student” and incidental learning as “the type of learning that is a by-product of doing or learning something else” （p.368）. Unlike intentional vocabulary learning， incidental vocabulary acquisition （IVA） is not based on the instructional focus in the classroom pedagogical setting， as Gass （1999） considered， but takes place “as a by-product of other cognitive exercises （e.g. reading/listening） involving comprehension” （p. 319）. Therefore， incidental vocabulary acquisition requires an understanding of the surrounding context of the unknown words， and the proper amount of attention the learner spends on both correct meaning and form of those words.

In this paper， the current literature theoretical models are reviewed on incidental vocabulary acquisition for the readers/learners during the L2 reading process. Next， some factors affecting incidental vocabulary acquisition in the L2 reading process are discussed. After illustrating the pedagogical implications， I finally provide a conclusion on the main concerns of this paper.

Theoretical Models in the Study of IVA

Currently， in many empirical studies， “Depth of Processing Model” and “Involvement Load Hypothesis” are frequently applied to testify the process and effect of incidental vocabulary acquisition from the aspects of cognitive psychology.endprint

Craik and Lockhart （1972） put forward the “Depth of Processing Model”， which illustrated that “memory trace can be understood as a by-product of perceptual analysis and that trace persistence is a positive function of the depth to which the stimulus has been analyzed” （p. 671）. This theory consists of two forms of cognitive processing： （shallow） formative and （deep） semantic processing. The depth of process of a stimulus has a great impact on its memorability when acquiring the new lexical items. However， Craik and Lockharts model has been refined in the following years， and their definition of processing level and cognitive effort is an oversimplification， which can not reveal the essence of the learners cognitive processing for the new lexical items.

With the further study of incidental vocabulary acquisition， Laufer and Hulstijn （2001） proposed the “Involvement Load Hypothesis”， which exemplifies the incidental vocabulary acquisition from the perspective of cognitive psychology. They stated that a construct of involvement in the tasks will have an impact on the learners retention of unfamiliar words. The amount of ‘involvement load contains three components： need （one motivational dimension）， search and evaluation （two cognitive dimensions）. Need represents the learners motivation for the target words. For instance， when a learner comes across an unfamiliar word affecting a reading comprehension， he/she will have a motivation to satisfy the reading tasks. Search takes place when the learner attempts to look for the meaning of the target words by checking a dictionary or asking the instructors. Meanwhile， Laufer & Husltijn （2001） defined that evaluation means a “comparison of a given word with words， a specific meaning of a word with other meanings or combing the words in order to assess whether a word （i.e. a form-meaning pair） does or does not fit its context” （p.14）. Therefore， tasks that induce the levels of need， search， and evaluation of meanings of unfamiliar words.

In terms of research approaches to incidental vocabulary acquisition in text comprehension， the interest of research has shifted from the product of the reading process in the previous research to the process of reading in current research. From the cognitive perspective， Rieder （2004） outlined how the reader builds a mental representation of textual meaning， “the reader processes the text， uses her language knowledge for retrieving the propositions mediated by the words and sentences and thus builds a propositional basis of the text meaning” （p. 55）. However， the required information could not be completely contained in the text. The reader has to activate world knowledge to build a representation of the content described by the text （Blakemore， 1992）. In the process of reading comprehension， the reader could construct his/her mental model by interacting the bottom-up and top-down processing to realize the shifting from textual level to word level so as to bridge the mental connections between the word of form and its denotational concept. On the contrary， reading is viewed as a cognitive process， neither the bottom-up nor top-bottom models can account for the whole reading process， and Rumelhart （1977） posited an interactive model， which regards the reading as a synthesis of patterns aiming for the integration of the previous knowledge resources in the text. Therefore， these dimensions decide on how much a learner can successfully build up the unknown word meaning， and how much effort the learner will invest in finding out the meaning.endprint

In summary， the conditions for the incidental vocabulary acquisition which a learner encounters in a reading comprehension rely on the availability of the resources required for clarifying the contextual meaning successfully， and the necessity for paying attention to this word. Therefore， the amount of incidental vocabulary gained will be aided by the type of resources used and how essential those resources are.

Factors Affecting IVA in the L2 Reading Process

Given the findings of previous and current research， many factors seem to be involved in successful incidental vocabulary acquisition for learners to do the reading comprehension， such as reading proficiency， vocabulary size， and reading tasks. The following factors are illustrated in combination with the empirical research.

Reading proficiency

Reading proficiency plays an important role in incidental word learning （Swanborn & De Glopper， 2002）. This finding is in line with the proposal of Sternberg and Powell （1983） that able and less able comprehensive readers show their different performance in the learning-form-context tasks. Pulido （2003） mainly investigated incidental vocabulary acquisition from the aspects of L2 reading proficiency， L2 passage sight vocabulary， and topic familiarity. The data showed that L2 reading proficiency and L2 passage sight vocabulary had significant effects on incidental vocabulary acquisition. The high-proficiency L2 readers and more L2 passage sight vocabulary acquired more unfamiliar words incidentally than those with low-proficiency L2 readers and less L2 passage sight vocabulary. Moreover， topic familiarity affected incidental vocabulary acquisition through reading as well.

Vocabulary size

Some scholars also identify another issue， the learners vocabulary size that would restrict the effectiveness of incidental vocabulary in English reading. Accordingly， some scholars in China and abroad emphasize the importance of vocabulary size for learners incidental learning in the reading process. As Restrepo Ramos （2015） suggested that “l(fā)earners must be able to recognize a great percentage of the surrounding words in order to correctly infer the meaning of a word in context”（p.164）. As suggested by Alderson （2005）， the importance of vocabulary use is that “the size of ones vocabulary is relevant to ones performance on any language test， in other words， that language ability is to quite a large extent a function of vocabulary size” （p.88）. Gai （2003b） claimed that “2000 to 3000 English words are needed first， and 5000 to 6000 English words must be commanded for college students for incidental vocabulary acquisition” （p.74）. Some hold that EFL learners could not acquire any new words from reading until they have commanded at least 5000 words first （Coady&Huckin， 1997； Nation， 2001）.endprint

Reading tasks

The significance of reading tasks for L2 learners vocabulary development is generally accepted by many scholars and educators. They have claimed that L2 learners can incidentally gain an amount of unfamiliar words while doing reading comprehension. Liu （2008） performed an experiment to prove the involvement load hypothesis. This experiment incorporated 81 non English major students in four groups to complete four separate reading tasks. These tasks included reading and answering questions， reading and completing a summary， reading and translating sentences， and reading and translating Chinese sentences. Another study investigating the influence of different tasks on incidental vocabulary acquisition was developed by Xu （2010）. This study tested what different reading tasks did for L2 learners with their immediate word gain and retention. Xu recruited 125 first year Chinese university ESL students， who， depending on their scores on their university entrance English examinations， were put in four separate groups. Reading comprehension tasks assigned to each group included glosses， sentence marking annotated target words， glosses and dictionary use， and no additional aid. From this study， it promoted the idea that tasks utilizing higher involvement load encourage the retention of more words.

The above-mentioned studies have paid attention to the reading tasks of facilitating L2 learners task-based lexical learning. In other words， reading plus tasks result in more and better lexical acquisition than sheer reading without tasks. This proves that reading tasks have been proven to greatly improve a learners lexical gain and retention.

Pedagogical Implications

Based on the forgoing discussion about the factors affecting IVA in L2 reading， some important pedagogical implications stem from this paper.

First， students reading proficiency is directly related to the effect of incidental vocabulary acquisition. Teachers should pay attention to the cultivation of their reading ability in this perspective. They can teach explicitly some of the contextual theory and word-formation knowledge in the class， enhancing their lexical inference strategies （e.g.， paragraphing， exemplification， restatement， comparison and contrast， parallel and parataxis， collocation， etc.）. Second， vocabulary can be enlarged by the way of building lexical semantic network. The lexical semantic network allows learners to form associative memory of the vocabulary so as to find out the difference and association between the words within the language. Finally， the importance of setting appropriate tasks is to make sure that when learners develop their vocabulary knowledge， they could involve more deeper and different processing in the reading tasks. In this case， it would allow learners to call attention to the lexical level and global text comprehension.endprint

Conclusion

This study discusses the findings that prove the occurrence of incidental vocabulary learning in the L2 reading process. This type of vocabulary learning relates to complex interacting processes and many influencing factors ensuring its success. As has been discussed by the empirical studies above， learners need to command an amount of words so as to infer an unfamiliar word in text. This could be facilitated by intentional vocabulary learning at the beginning of the rote instruction， which allows the following up of more incidental vocabulary learning. On the whole， although some issues and possibilities have explored in this study， further efforts are needed to focus on how we can implement the additional technology aids in our future teaching and learning research on English vocabulary acquisition.

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作者簡介：袁勤（1981-），女，湖北沙市人，三亞學(xué)院外國語學(xué)院英語系講師，加拿大維多利亞大學(xué)語言學(xué)系在讀博士研究生，研究方向第二語言習(xí)得，英語教學(xué)法， 跨文化研究。endprint