Vocabulary learning

One of the major types of vocabulary learning in language acquisition is deliberate vocabulary learning. Before moving on to presenting the literature, it is important to mention that when talking about deliberate vocabulary learning, various terminologies are used by different linguists and writers. Elgort and Warren (2014), as well as Schmitt (2000), use the term explicit (which is mostly used for grammar teaching), while Nation (2006) uses the word decontextualized vocabulary learning and contrasts the term with "learning from context" (p. 494) without explicitly using the term incidental vocabulary learning. Intentional vocabulary learning (Dodigovic, Jeaco & Wei, 2017; Hulstijn, 2001), active learning (Thornbury, 2002), and direct instruction (Lawrence et al., 2010) are also used. However, throughout this paper, the term deliberate (Elgort, 2011; Nation, 2006) will be used to refer to this concept.

The advocates of deliberate vocabulary learning paradigm -for example, Coady, 1993; Nation, 1990, 2001, as cited in Ma & Kelly, 2006- agree that context is the main source for vocabulary acquisition. However, they also believe that in order to be able to build up sufficient vocabulary and acquire the necessary strategies to handle the context when reading, learners need support. Thus, extensive reading may be sufficient for developing advanced students’ vocabulary, but it has to be supplemented with deliberate vocabulary learning at lower proficiency levels (Elgort & Warren, 2014). Kennedy (2003) supports this notion and argues that deliberate learning is more appropriate for students with up to an intermediate level of proficiency, while incidental learning, which can occur outside the classroom, is more valuable with higher proficiency students. The limited classroom time should be spent on the deliberate teaching of vocabulary (Schmitt, 2000), as the main problem of vocabulary teaching is that only a few words, or a small part of what is required to know a word, can be taught at a time (Ma & Kelly, 2006). Ma and Kelly (2006) argue that learning a word requires more “deliberate mental effort” than merely being engaged in meaning-focused activities. However, according to the authors, the advocates of deliberate approach believe that it should be combined with incidental learning to be more efficient.

Schmitt (2000) demonstrates that deliberate vocabulary learning, unlike incidental learning, is time-consuming, and too laborious. Moreover, according to Nation (2005), deliberate vocabulary learning is “one of the least efficient ways” to improve students’ vocabulary knowledge. Yet, he claims that it is a vital component in vocabulary teaching programs. However, Schmitt (2000) states that deliberate vocabulary learning gives the learners the “greatest chance” for acquiring vocabulary, as it focuses their attention directly on the target vocabulary. He presents an important concept from the field of psychology: “the more one manipulates, thinks about, and uses mental information, the more likely it is that one will retain that information” (p. 121). The deeper the processing, the more likely it is for the newly learned words to be remembered. Therefore, explicit attention should also be given to vocabulary, especially when the aim is language-focused learning (Nation, 2006b). According to Ellis (1994, as cited in Laufer & Hulstijn, 2001), while the meaning of a word requires “conscious processing” and is learned deliberately, the articulation of its form is learned incidentally because of frequent exposure. Ma and Kelly (2006) mention the necessity of establishing a link between the meaning and form of a word by various strategies, e.g., “direct memorization,” which is a strategy of deliberate vocabulary teaching.

In vocabulary teaching programs, it is also necessary to consider the frequency of the words (Nation, 2006b). Thus, high-frequency words deserve to be taught explicitly (Kennedy, 2003) and sometimes even low-frequency words can be taught and learned deliberately, for example through word cards, word part analysis, and dictionary as recommended by Nation (2006b). However, when measuring the difficulty by the results, deliberate vocabulary learning is easier than incidental learning, yet it needs more focused effort. Therefore, directing deliberate attention to the particular aspect can lighten "the learning burden" (Nation, 2006a).

To sum up, deliberate vocabulary learning is essential to reach a threshold of the vocabulary size and it is a prerequisite to incidental learning (Schmitt, 2000).

Another type of vocabulary learning is called incidental vocabulary learning. By its nature, incidental vocabulary learning is one of the key aspects of language acquisition. This concept, which is also referred to as passive learning (Shmidth, 1990; as cited in Alemi & Tayebi, 2011) or implicit learning (Gu, 2003), is the process of acquiring vocabulary without placing the focus on specific words to be learned (Paribakht & Wesche, 1999). It is deemed that, this type of learning should occur with low-frequency words (Nation, 2005) as the first few thousand words are better learned through deliberate learning approach (Huckin & Coady 1999). However, this may be hampered by the fact that several encounters with a word are needed before it is committed to memory (Nation, 1990), which may not be possible with low-frequency words (Nation 1990). Aelmi and Tayebi (2011) as well as Schmitt (2000) link incidental vocabulary learning with the communicative context. The formers stress that incidental vocabulary learning occurs by "picking up structures and lexicon of a language, through getting engaged in a variety of communicative activities" (p. 82), while the latter indicates that producing language for communicational purposes results in incidental learning.

There is a number of factors which affect the occurrence of incidental vocabulary learning. Most of the scholars agree that the best way is through extensive reading (Jian-ping, 2013; Restrepo Ramos, 2015). Restrepo Ramos (2015) indicates that “there is strong evidence that supports the occurrence of incidental vocabulary learning through reading for meaning comprehension” (p. 164). However, as research shows, 95% of the words must be familiar to the reader to understand a text (Hirsh & Nation, 1992; Laufer, 1989). According to Nation (2009), this figure is even higher, i.e., 98 percent. Huckin & Coady (1999),[2] on the other hand, argue that "extensive reading for meaning does not automatically lead to the acquisition of vocabulary. Much depends on the context surrounding each word, and the nature of the learner's attention" (p. 183). While Dodigovic (2015) finds that it is the approach that matters, i.e., the bottom-up processing of readings is better than the top-down. Thus, to develop incidental vocabulary learning, the learners should be exposed to the words in different informative contexts, following the bottom-up processing of the readings.