Vocabulary Acquisition in the Second Language

The importance of vocabulary in general language acquisition and communication (first and second) cannot be denied (Clark, 1993; Dagut, 1977; Harley, 1995; Laufer, 1990b; Singleton, 1999, 2000; Smith & Locke, 1988; Yoshida, 1978). The process of L2 vocabulary acquisition begins as soon as the L2 is encountered and continues long after other aspects of the L2 have been mastered. Despite being such a central and durative phenomenon, there are still many aspects of the L2 vocabulary acquisition process that remain mysterious, as Schmitt (1998: 281) points out: '[t]he mechanics of vocabulary acquisition is one of the more intriguing puzzles in second language acquisition'. This chapter explores L2 vocabulary learning with a particular focus on young learners' vocabulary acquisition. Accounts of differences in L1 and L2 lexical development processes as well as the relationships between the L1 and L2 lexicons are also dealt with in this chapter.

There has been copious research in lexical development in L1 and L2, but the absence of an overarching psycholinguistic framework to interpret these studies results in a fragmentation of the field, with studies addressing, for example, vocabulary size, different dimensions of word knowledge, passive/active distinctions in respect of vocabulary knowledge, reception and comprehension, vocabulary instruction and vocabulary learning strategies. In 1988, Channell already noted this problem:

There are now theories of L2 vocabulary acquisition, a wide (and growing) range of teaching techniques available, and a greatly increased awareness on the part of most teachers (and learners) of the importance of vocabulary development. At the same time, understanding of the psychological aspects of L2 vocabulary acquisition and vocabulary use is still rather limited. (Channell, 1988: 83)

Hudson (1990) also recognized this general area of deficit.

To my knowledge, a systematic model of how meanings of words are acquired is absent from the field. Most writers on the subject assume L2 lexical development proceeds in the same way as in a first language (L1), without specifying what this is in formal terms. (Hudson, 1990: 222)

The situation has not changed much in the last decade, although research on L2 vocabulary learning has significantly increased. The most frequently brandished explanation of L2 vocabulary learning extends L1 research findings to the learning of vocabulary in an additional language, on the basis of a view that the L2 lexicon is operationally similar to the L1 lexicon and that L1 and L2 lexical acquisition and processing follow in at least comparable ways. Thus, the findings in respect to L1 lexical processing are also seen as relevant to L2 (Singleton, 1999: Chap. 3; Stoller & Grabe, 1995). The fact, however, that L2 learners have already started developing their L1 lexicon by the time L2 acquisition begins may imply some differences between L1 and L2 lexical development (Singleton, 1999: Chap. 2). We further deal with this issue later. Our focus to begin with is on the different theories that attempt to explain vocabulary acquisition.

Theories of Vocabulary Acquisition in the Second Language

There are a number of disparate stances regarding the nature of L2 vocabulary acquisition, but two main complementary approaches can be distinguished, each emphasising different aspects of the process. The first focuses on the development of vocabulary as a process in stages (cf. Ellis, 1997a: 133ff; Jiang, 2000; Schmitt, 1998). The second represents vocabulary acquisition as the development of associative networks (Meara, 1984, 1996).

Vocabulary acquisition as a process in stages

One possibility is that vocabulary develops in consecutive stages. Researchers have made attempts at discovering some systematicity in how vocabulary items are acquired, trying to isolate predictable stages of acquisition. Thus, Gleitman and Landau (1996: 1) claim that vocabulary learning is not just the result of a mapping procedure, but that there is a systematic process at work comparable to the highly structured innate principles that guide syntactic acquisition.

The study of vocabulary acquisition in this perspective can have a number of dimensions: (1) order of acquisition of different types of knowledge (morphological, syntactic, collocational, semantic, etc.) for each lexical item, (2) order of acquisition of word classes (noun, verb, adverb, adjective, etc.), (3) order of acquisition of particular lexical items and (4) developmental stages of lexical processing.

Concerning the first, Schmitt (1998) advocates the study of the acquisition of individual words diachronically. In his 1998 article, for example, he measured the developmental acquisition of four types of word knowledge: written form, associations, grammatical behaviour and meaning. The study was intended to find out whether there is any hierarchical relationship between these four aspects of word knowledge. None of the measures used yielded positive evidence of a developmental hierarchy of lexical competence components. Other studies that follow the same line have been equally unsuccessful in identifying the stages through which lexical acquisition might develop. However, the existence of some regular patterns of vocabulary development is generally acknowledged (cf. Curtis, 1987: 45; Palmberg, 1987; Schmitt & Meara, 1997; Viberg, 1996; Yoshida, 1978). Naturalistic observations of L1 lexical development support the idea that knowledge of a word is not a yes/no issue. New words and word aspects are acquired in an incremental way. Different aspects of word knowledge, for example morphological knowledge, collocations, appropriate use of lexical items in context or knowledge of polysemous words, seem to be incorporated to the lexical entry at different moments during the L2 acquisition process. Similarly, lexical items belonging to a different word class appear to undergo different rates of acquisition, with nouns being acquired first and verbs second (Ellis & Beaton, 1993; Laufer, 1990b, 1997b; Marsden & David, 2008; Myles, 2005; Singleton, 1999: 141-142).

Research on word class acquisition is not very copious, but some recent studies by Marsden and David (2008) and Myles (2005) have claimed that verb production increases as learners' L2 proficiency develops. Parallel to this increase in verb production, there is, in this view, a decrease in noun production. Low-proficiency learners' productions abound in nouns, but verbs are practically non-existent in such productions. The...