Acquisition Criterion

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the accuracy of the research results (Jansen cited in Di Biase, 2002; Trott et al., 2004). To determine when a certain grammatical structure or feature became part of the informants’ L2 grammatical system and to check whether the hypothesized structures are acquired in a predicated order (Zhang, 2004), it was necessary to first decide the acquisition criterion - a thorny issue in PT.

In a PT concept, the notion of ‘acquisition’ indicates that the ability to process the specific structure has been acquired. When can we say that a particular structure is acquired? Which level of development is the learner at? Even though the exact criterion is different in range, its ‘underlying goal was to measure the acquisition outcome by comparing the L2 performance against the target language norm’ (Zhang, 2004: 449).

Cox (2005) has summarized and explained that the criteria used to measure morpheme acquisition can be categorized and termed as Mastery, Grading and Emergence. A few research projects have been carried out to test the different feasibilities of applying these three criteria for language acquisition.

In the accuracy-based acquisition criterion, a certain accuracy rate was set up to measure the success or failure of learners’ acquisition or to assess their acquisition process. Brown, for instance, in his 1973 study on L1 English language acquisition, set a 90% suppliance as the mastery criterion. De Villiers and De Villiers (1973) also employed the mastery criterion which present in 90% of the obligatory contexts in their study. In addition, Meerholz-Hårles (2001) calculated the percentage of accuracy and used the rank of accuracy as the acquisition criterion in his study. However, an issue when using mastery criterion occurred: why not 80% instead of 90%? Does rank of accuracy equate with developmental sequences, and if yes, to what extent? In this case, if 80% is adopted as the accuracy rate, the learner who presents 79% correct forms in a particular structure will be judged as having no acquisition of this structure at all.

Pienemann and Kessler (2007) drew a figure to illustrate that for any learners and structures, suppliance in obligatory contexts may develop in different patterns. The

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rate of suppliance of structures a, b and c increases in different ways, as shown in Figure 5.1:

Figure 5.1 Accuracy and Development (Pienemann and Kessler, 2007: 14)

This figure shows that the accuracy rate is an invalid measurement for language development in a linear manner. Obviously, the three lines have a different gradient. In this case, if we use the 50% as the criterion, the order of acquisition is c>b>a, yet while using the 100% as the criterion, the order of the acquisition will be altered as c>a>b; therefore, the results are very unreliable.

The assumption of a correspondence between accuracy and acquisition order has been challenged by many scholars in SLA. For instance, Pienemann (1998c: 137) pointed out that neither accuracy measures nor the target language norm could be set up as acquisition criterion for the examination of the L2 acquisition process, as ‘accuracy rates develop with highly variable gradients in relation to grammatical items and individual learners’. Pienemann (1998c) has also stated that the accuracy of morpheme insertion will not guarantee that the acquisition increases steadily.

Therefore, another measurement for SLA development has been introduced: a grading criterion. A graded system is used in the International English Language Testing System (IELTS) exams. IELTS exams employ such a points system to note and grade the levels of language production complexity, and the accuracy of using vocabulary and grammar in learners’ speeches. The test-takers language competence has been divided into 9 levels with a descriptive measurement in each level. In this case, nevertheless, subjective views or bias on language production have largely controlled the learners’ test results. However, this grading system could not present the whole picture of the continuous accumulation of grammatical resources to a target

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language; thus the speakers’ acquisition trajectory with sufficient supporting evidence is hardly obtained from this measurement.

The dynamic description of IL development goes far beyond a mere description of orders of accuracy. On this topic, Larsen-Freeman and Long (1991) have mentioned that the emergence criterion aims to make sure that the starting point of acquisition, which exposes the whole process of language acquisition. Pienemann (1998a and 1998c) and Zhang (2002a) have then adopted this criterion to identify the acquisition route in processability studies, since emergence can be understood as the point of the first emergence of a structure in time, at which certain skills have been attained during speech processing.To expand further, Cox (2005) then compared emergence criterion and mastery criterion, and found that the findings undermined the very usefulness of emergence criterion which is capable of producing a meaningful morpheme acquisition order.

From another perspective, to employ emergence criterion is to avoid the subjects producing morphemes due to a formulaic memorization of a chunk. In the words of Pienemann (1984: 191):

The main purpose is not to describe the point in time during the process of language development when a structure is mastered (in terms of correct use of target norms), because this is only to pinpoint the end of the acquisition of a certain structure. Rather, the [emergence] criterion is intended to define the first systematic use of a structure, so that the point in time can be located when the learner has – in principle – grasped the learner task …

For these reasons, the acquisition criterion used in PT is ‘emergence’, which identifies the point and signifies that a certain procedural skill has been operational in a learner’s IL system (Kawaguchi, 2005c).

In accordance with the emergence criterion, Pienemann (1998b: 146) categorizes quantitative production of a learner language into four types, namely: ‘(1) no evidence, i.e. no linguistic contexts; (2) insufficient evidence, i.e. a very small number of contexts; (3) evidence for non-application, i.e. non-application in the presence of contexts for rule x; and (4) evidence of rule application, i.e. (sufficient) examples of rule application in the presence of contexts’.

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In a number of research contexts, it has been pointed out that there are different type-token ratio measures based on emergence criterion (Kawaguchi, 2002; Pienemann, 1998c; Zhang, 2003). The data is summarized in terms of quantitative figures and ratios to outline an approximate indication of the learner’s dynamic IL system.

Actually, the minimum number of the rule application contexts or tokens to test the productive nature of an IL grammatical feature is not definitely set up in the emergence criterion, as it varies among research studies. Lee (1996) has considered the emergence of a grammatical item as being when it has been used correctly once in the data collection, as long as this instance is not a formula or chunk. Kawaguchi (1996) applied three different emergences of grammatical points as the measurement of acquisition. Pienemann (1998c) and Zhang (2001) set the emergence point as four times, while Clahsen (1984) set the emergence point as five times. In an early study of De Villiers and De Villiers (1973), they scored results only if they were based on at least five obligatory contexts.

Obviously to see, evidence of rule application in one context is not reliable, nor is it in two contexts, in which a 50% rule application indicates only one token (Pienemann, 1998c). Usually between three and five contexts are used to test acquisition hypotheses.

However, if one student has produced three pieces of valid evidence to prove his/her acquisition of a certain structure, he/she is identified as acquired of this structure in a study where three evidences are required, but is signified as not acquired in another study where four obligatory evidences are required. Is it unreliable? The fact speaks. If one student could not operate the structures in the next stage, he/she should be ‘bounced’ back to the previous one for more study. The opposite is also true - if the students have already acquired the structure but did not present enough required items, further study could help them to reinforce the use of the grammatical items. On this basis, Pienemann (1998a) has suggested and concluded that as long as the learners can present the grammatical structures in a variety of environments, any

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emergence points (three times, four times, five time, etc.) could be applicable. Therefore, to check whether the hypothesized structures are acquired in the predicted order in my study, I should clarify the notion of ‘acquisition’ (which is used for PT) to answer the question: ‘which type of procedural skill has been acquired?’ The present study has employed the ‘emergence criterion’ proposed in Pienemann (1998c) as being four times, which tends to remain constant. The decision was made due to the following two reasons: 1) this emergence point has been applied in other PT studies successfully, and 2) the frequency of data collection is 10 times over a 38-week period. As for the length of the data collection and the sufficient speech data collected, a 4-point emergence criterion seems to be more practical.

In this case, all the utterances in the data set were coded for grammatical features along with their functional and structural contexts. A certain structure in the learners’ data sample sets was viewed as having emerged if a minimum of four tokens had been observed with lexically-varied contexts (to decrease the risk of chunk-learning); otherwise, the frequent emergence may be due to the production of an unanalyzed unit or syntactic pattern.

In simple terms, for example, if the possessive marker –de occurred exclusively with the same pronoun, in this case –de (POSS) would not be considered as having emerged in spite of the number of the tokens appeared. If –de (POSS) occurred with different pronouns in lexically-varied contexts a minimum of four times in a learner’s speech sample set, it was counted as having emerged in the learners’ L2 grammatical system, regardless of the number of tokens in a sample.

In brief, the emergence criterion allows the understanding of the whole processing picture of language acquisition. Significantly, it is crucial to ensure that the developmental stage emerged is systematic and not acquired as a regular block.