Organización y secuenciación temporalizada de los

Since it is impossible to deal with the creation and validation of the tests of all six aspects of VLP in a single PhD, this thesis focuses on two of them: guessing from context and knowledge of word parts. This section discusses the reasons why it might be more important to measure the skill of guessing from context and knowledge of word parts than other aspects of VLP.

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The first reason for the creation of the two tests is that there have been no validated tests that measure the skill of guessing from context and knowledge of word parts. Existing tests of guessing from context may not be useful for detecting learners’ weaknesses, because the tests are not easy to complete and grade (e.g., Haastrup, 1991) or the tests do not measure multiple aspects of guessing (e.g., Schatz & Baldwin, 1986) (see Section 3.4 for a review of the existing tests of guessing from context). Existing tests of word part knowledge may also have limitations, because the tests do not measure multiple aspects of word part knowledge (e.g., Wysocki & Jenkins, 1987) or a limited number of word parts are measured (e.g., Schmitt & Meara, 1997) (see Sections 5.5.2.1., 5.5.3.1, and 5.5.4.1 for a review of the existing tests of word part knowledge).

The skill of guessing from context plays a key role in vocabulary learning, because it is the most frequent and preferred strategy when learners deal with unknown words in context. Paribakht and Wesche (1999) conducted an introspective study with ten intermediate ESL learners with various L1 backgrounds, and found that the participants used guessing from context for 80% of the unknown words whose meanings they actively tried to identify. Fraser (1999) also conducted an introspective study with eight Francophone university students, and found that guessing was the most frequent strategy (44%) of all the strategies employed (consult = 29%; ignore = 24%; other = 3%). Cooper (1999) examined strategy use for dealing with unknown idioms with 18 ESL learners with a variety of L1 backgrounds, and found that guessing was the most frequent strategy (28%) of all the strategies employed.

Although guessing is the most frequent strategy for dealing with unknown words in context, learners’ guesses often result in failure. Nassaji (2003), in a study with 21 ESL learners with various L1 backgrounds, found that they made correct guesses for

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25.6% of all unknown words and 44.2% of these items if partially correct guesses were included. Similar results were obtained in a study by Parry (1991), in which the four participants’ ratios of correct guesses to the total number of guesses ranged from 12% to 33%. These low success rates suggest that there is much room for improvement in the guessing strategy. Creating a guessing-from-context test may diagnose learners’ weaknesses in guessing and contribute to the improvement of the guessing strategy.

Guessing from context may be a major source of vocabulary learning where vocabulary learning occurs while reading and listening. The importance of vocabulary learning through reading and listening can be seen in a number of previous studies that provide positive but modest evidence for gains in vocabulary knowledge for both L1 acquisition (Jenkins, Stein, & Wysocki, 1984; Nagy, Anderson, & Herman, 1987; Nagy, et al., 1985; Shu, Anderson, & Zhang, 1995) and L2 acquisition (Brown, et al., 2008; Day, et al., 1991; Dupuy & Krashen, 1993; Horst, et al., 1998; Hulstijn, 1992; Pitts, et al., 1989; Waring & Takaki, 2003). It is argued that the vast majority of words are learned while reading and listening especially for L1 acquisition (Nagy & Anderson, 1984). For L2 acquisition, vocabulary learning through reading and listening may become important especially when learners have gained knowledge of high-frequency words that appear in a wide variety of texts. This is because teachers may have little time to deal with a daunting number of low-frequency words in class and learners may need to increase their vocabulary knowledge on their own while reading or listening to the texts that are of interest to them. Taken together, the improved skill of guessing has the potential to facilitate vocabulary learning through reading or listening, because learners rely on the guessing strategy most frequently when dealing with unknown words in context and good guessers are likely to have a greater opportunity to derive the

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appropriate meaning of an unknown word and learn it.

The second aspect of VLP examined in this thesis is knowledge of word parts. For English learners, this knowledge is of great value because about half of English words are morphologically complex (Anglin, 1993; Goulden, Nation, & Read, 1990; Nagy & Anderson, 1984). In addition, a corpus-based study by Nagy and Anderson (1984) indicated that an increasingly greater proportion of semantically transparent words appear as the word frequency goes down. This suggests that knowledge of word parts is useful especially for the learning of low-frequency words which may not be taught in class and thus need to be learned independently.

Another advantage of word part knowledge is that it may help learners check whether an unknown word has been successfully guessed from context (Mori, 2002; Mori & Nagy, 1999; Nagy & Anderson, 1984; Nation, 2001). In other words, integration of information from context and word parts may make guessing more successful and contribute to effective vocabulary learning. Being aware of the two sources of information is of great importance because word meanings may not easily be determined by a single source of information. Research (Beck, McKeown, & McCaslin, 1983; Schatz & Baldwin, 1986) indicates that contextual clues are not always sufficient for deriving the meanings of unknown words. Research (Bensoussan & Laufer, 1984) also indicates that learners may be misled by some deceptive word parts (e.g., bother is not both + -er).

Finally, knowledge of word parts and the skill of guessing from context may be the most useful strategies for learners because these strategies may be used in any situation for any words. Both strategies do not require supplementary materials such as word cards and flash card software. The skill of guessing is available when learners read or

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listen to virtually any material (e.g., novels, newspapers, and movies) and thus learning occurs both inside and outside the classroom. It may also make learning pleasurable because learners can read or listen to any material that is interesting to them. Knowledge of word parts is also useful because it is widely available for learning word families (morphologically and semantically related words). Research (Nagy & Anderson, 1984) shows that every word has more than one derivative on average (1.57 – 3.22 derivatives excluding inflections depending on the difference in the definition of semantic relatedness), indicating that knowledge of affixes may help expand vocabulary rapidly.

For the above-mentioned reasons, this thesis created and validated tests of guessing from context and knowledge of word parts. An in-depth review of the literature on how these two aspects of VLP have been measured will be provided separately in Chapter 3 for guessing from context and Chapter 5 for knowledge of word parts so that it may be easier to recognise the difference between the formats used in previous studies and the format used in this thesis.