Individual Differences in Second Language Acquisition

Learners are different in the way they learn a second language. They differ in the rate of acquisition and in their level of achievement and these differences determine the success or failure of learners in language learning (^{Li, 2015}). Therefore, individual differences among learners seem to be an essential part of learning process and because of its importance, language learning process has emerged as its own field of study (^{Nitta, 2006}). ^{Ellis (2008)} reported that “in earlier periods learners were viewed in absolute terms, as innately endowed with or lacking in language learning skills” (p. 525) because the primary concern was to predict which learners would be successful in language learning. However, “in more recent research learners are seen as having different kinds of abilities and predispositions” (p. 525) for language learning, so the reason why some learners were more successful than others in language learning has been a basis for the studies on learner differences.

There are many factors which create a difference among individual learners. They can be classified in three groups: affective, social and cognitive factors (^{Ellis, 2008}). While the social factors include the effect of socio-economic environment on learning, the affective and the cognitive factors lie inside the learner and they include language aptitude, motivation, anxiety, learning style and personality (^{Nitta, 2006}). According to ^{Ellis and Shintani (2014)}, language aptitude had a more consistent correlation to language achievement than style and personality. Therefore, it is clear that language aptitude is strongly related to learners’ outcomes in language learning (^{Dörnyei, 2010}; ^{Singleton, 2014}).

Language Aptitude

In recent decades, language aptitude has attracted more and more attention because it has been found to be one of the most important factors in second language learning, so many researchers have tried to define language aptitude in the context of learning (^{Wen, Biedroń, & Skehan, 2017}). To illustrate; according to Carroll and Sapon (as cited in ^{Li, 2015}) language aptitude refers to “a set of cognitive abilities that are ‘predictive of how well, relative to other individuals, an individual can learn a foreign language in a given amount of time and under given conditions’” (p. 386). It is obvious that language aptitude can predict learners’ language achievement. Moreover, ^{Robinson (2001)}) sees language aptitude as a cognitive ability to process information for language learning (^{Li, 2015}). Language aptitude could make learning easier for pre-service language teachers through the use of cognitive strategies such as repetition, guessing meaning, organizing new language etc. All in all, it can be said that language aptitude is a special ability which is important for second or foreign language learning (^{Elmechta, 2016}).

Language aptitude is an umbrella term which consists of four components proposed by John Carroll (^{Ellis, 2008}). The first component is phonetic coding ability and ^{Rysiewicz (2008)} defined it as “the ability to segment and identify (code) distinct foreign sounds, to form associations between them and graphemic symbols representing them for later use” (p. 572). As can be understood from this definition it is necessary to code the sounds and match these sounds with their orthographic representations so that they can be used to speak the target language effectively (^{Moskovsky, Alshahrani, Ratcheva, & Paolini, 2015}). Through mental processes such as coding, assimilation and remembering, learners can learn second or foreign languages easily (^{Elmechta, 2016}).

The second component is grammatical sensitivity which is defined by Robinson (as quoted in ^{Piraud, 2008}) as “the ability to recognize the grammatical functions of words (or other linguistic entities) within sentences” (p. 99). Broadly, the grammatical sensitivity refers to the awareness of syntactic patterns in sentences and different levels of grammatical sensitivity among pre-service language teachers can affect their language learning, to illustrate, the learners with high grammatical sensitivity recognize linguistic patterns easily and quickly (^{Piraud, 2008}). Additionally, ^{Carroll (1968)} states that reading and writing require high level of grammatical sensitivity and learners have to work out grammatical analysis to learn a foreign language. Therefore, the grammatical sensitivity is an important aspect of language aptitude which enhances language learning.

The third component is inductive learning ability which enables learners to induce grammatical rules from language samples (^{Li, 2015}). Through the inductive learning ability learners can become independent thinkers and they can take an active role in learning the forms and meanings of linguistic patterns (^{Herron & Tomasello, 1992}). Moreover, grammatical sensitivity and inductive language learning ability are higher skills which are strongly correlated with L2 success (^{Moskovsky et.al, 2015}). Therefore, the inductive learning ability is one of the key aspects of language aptitude which makes the mappings between forms and meanings of linguistic features possible for learners (^{Carroll, 1968}).

The fourth component of language aptitude is rote learning ability which is based on associative working memory (^{Cowan, 2014}). ^{Wen and Skehan (2011)} views the working memory as “a combination of storage and manipulation” of information (p. 4) and second language acquisition is based on cognitive resources including working memory and in different stages of language learning which are input processes, central processing and output processing, the working memory facilitates noticing and processing the language patterns. Therefore, it is clear that working memory is an essential aspect of language aptitude because it helps learners keep information and use this information during the learning process (^{Ellis & Sinclair, 1996}). In short, the four components of language aptitude can be summarized in Table 1.

As a result, language aptitude is a significant variable to examine pre-service language teachers’ achievement in language learning because it includes different abilities which have a positive influence on pre-service language teachers’ language learning process, so whether aptitude really plays a role in ultimate attainment is an important research interest (^{Grymska, 2016}).

Historical Overview of Language Aptitude

The field of language aptitude has a long history and the research in this area started with the American educational psychologist John Carroll’s study on the concept of foreign language aptitude in the 1950s (^{Rysiewicz, 2008}). In his study, Carroll emphasized that individual learners have different capacities to learn foreign languages easily and speaking a foreign language requires a special talent which is the language aptitude (^{Wen et al., 2017}). Moreover, Carroll and his colleague Sapon developed the Modern Language Aptitude Test (MLAT) battery in 1956 to measure individual learner’s aptitude for a foreign language learning and this battery paved the way for subsequent aptitude measures such as The Pimsleur Language Aptitude Battery (PLAB), so it is seen as the most influential aptitude test in this field of study (^{Li, 2015}).

After the publication of MLAT, research on language aptitude continued mainly in three different areas (^{Wen & Skehan, 2011}). One of them was about the development of aptitude tests, so alternative tests to MLAT such as Al-Haik’s Defense Language Aptitude Battery (DLAB). Al Haik developed an alternative test called Defense Language Aptitude Battery (DLAB) to determine armed service members’ ability in a foreign language (^{Wen et al., 2017}). The other research area focused on the components of language aptitudes, additionally, the studies measuring the aptitude levels of learners and their relation with motivation and achievement exponentially increased because it was believed that they would provide pedagogical implications for L2 learning (^{Wen & Skehan, 2011}).

Starting from the 1970s, however, the research on language aptitude has slowed down because the concept of language aptitude was criticized for two reasons: for its origin associated with the outdated audio-lingual methodologies and for the low aptitude score which labels a language learner as an untalented person in learning a new language (^{Li, 2015}). Nonetheless, in the course of time these two criticisms that aptitude was rooted in the audio-lingual method and that without aptitude, learners cannot acquire a language have been invalidated in many studies highlighting the role of memory (^{Archibald, 2017}; ^{Baddeley, 2012}; ^{Desmond & Fiez, 1998}) and the concept of language aptitude has gained momentum (^{Grymska, 2016}).

Achievement and Language Aptitude

The correlation between learners’ language aptitude and their achievement levels in English has been a research subject for many years. However, there are contradictory results in this research area because of the difficulty of determining learners’ language aptitude which is a multi-component concept consisting of phonemic decoding, grammatical sensitivity, inductive association and memory (^{Wen et al., 2017}). Even so, past studies give an implication for the present study of the correlation between learners’ language aptitude and their English achievement level.

Some studies in this area show that there is a significant relation between pre-service language teachers’ language aptitude and their English achievement. To illustrate; ^{Wang and Wu (2017)} investigated the influence of language aptitude on EFL pre-service language teachers at Beijing University through Modern Language Aptitude Test (MLAT). The results showed that there was a correlation between language aptitude and English learning, so the pre-service language teachers who got high scores from MLAT were better especially in writing and reading skills (^{Wang & Wu, 2017}). Another study in a different context shows similar results. In this study, ^{Moskovsky et al. (2015)} conducted a research on first-year Saudi university pre-service language teachers to examine the extent to which aptitude predicts second language achievement. Pre-service language teachers were given Aptitude and English proficiency tests. Pre-service language teachers with the high aptitude test scores were more successful than the ones with the low aptitude test scores especially in literacy skills (^{Moskovsky et al., 2015}). Moreover, ^{Elmechta (2016)} investigated the impact of language aptitude and working memory on language learning achievement. The language aptitude measure and the working memory measure were given to pre-service language teachers at Mentouri Brothers-Constantine University. Results showed that the university pre-service language teachers with higher working memory capacity were more successful in language learning. As a result, working memory and aptitude showed a significant association with achievement (^{Elmechta, 2016}).

There are also some studies which show that there is not a significant relation between language aptitude and achievement. For instance, the predictive validity of the Graduate Record Examinations (GRE) aptitude test has been investigated for foreign students at the University of Kansas by ^{Kaiser (1983)}. A total of 148 students whose first language was other than English were selected for this study. Verbal and quantitative scores on the GRE, field of study, sex, and year of initial enrollment were used as predictors. The grade point average (GPA) in the graduate school was considered as the criterion. The results revealed that foreign students scored significantly lower than American students on the GRE scores. Poor correlation between the GRE scores and the criterion suggested that the GRE aptitude test is not the most appropriate way to predict academic performance of foreign students. Additionally, ^{Goodman, Freed and McManus (1990)} investigated the relation between university pre-service language teachers’ language aptitude scores and their semester grades. At the University of Pennsylvania 586 pre-service language teachers were given Modern Language Aptitude Test (MLAT) and only a weak correlation between MLAT scores and pre-service language teachers’ grades was found (^{Goodman et al., 1990}).

Although some research findings point to a close relation between language aptitude and achievement, other studies do not show any relation of language aptitude with achievement. Therefore, uncertainty remains in this research area, so to provide a better insight into this area, two questions will be answered in the present study:

Participants

This study was conducted with 72 pre-service language teachers at English Language Teaching (ELT) department. Their ages varied between 18-20. The department they studied at offered four-year long courses on methodology, applied linguistics, sociolinguistics, research design, information technologies conducted in English. The participants were selected through the stratified sampling method. Since they were almost eligible to be qualified as English language teachers, their proficiency levels were C1. The reason why pre-service language teachers were selected as the study group was that their proficiency levels were higher than the average learners. Before coming to study at the English Language Teaching Department that they studied for four years, they had already passed two national tests given on English proficiency by the Higher Council of Education.

Instrument

In this study, the purpose was to investigate the correlation between pre-service language teachers’ language aptitude and their English achievement levels was investigated. Data were obtained through a verbal aptitude test which was modified from the psychometric success site of the university where the researchers worked. It was adapted and pilot-tested for the reliability, which was .78. The verbal aptitude test included 42 questions related to the four components of language aptitude, so the questions measure pre-service language teachers’ phonemic coding ability, grammatical sensitivity, inductive language learning ability and rote learning ability. Some sample questions are listed below:

1) Find out the incorrect spelling

A) occurence

B) dissipate

C) weird

D) accommodate

E) embarrassment

2) Which of these is the missing word? water, -----------, over

A) ice

B) drive

C) wet

D) flow

E) fall

3) Which of these words is the odd one out?

A) swindle

B) harass

C) provoke

D) annoy

E) pester

Moreover, pre-service language teachers’ grade point averages from all the English medium-based courses at school (GPAs) were obtained to find a correlation between pre-service language teachers’ language aptitude and achievement levels.

Procedure

The verbal aptitude test was administered to pre-service language teachers during their Applied Linguistics Seminar class. All of the pre-service language teachers were informed about the aim of this study. Their consents forms were taken and they were asked to complete the verbal aptitude test. They were also asked to write their GPA (their grade point average for the department) English exam scores on the sheet.

Data Analysis

The data were analyzed through Statistical Package for the Social Sciences (SPSS) program. In this program, the Spearman Product Moment Correlation Coefficient analysis was used to determine whether there is a correlation between pre-service language teachers’ language aptitude and their English achievement levels.

Data Results

In the present study, the findings are discussed in relation to the two research questions:

The mean and standard deviation values were calculated to elicit pre-service language teachers’ language aptitude. According to the findings, the mean of the total aptitude scale is .35 which shows that pre-service language teachers have a low level of language aptitude.

In the present study, the findings are discussed in relation to the four components of language aptitude test which are phonetic coding ability, grammatical sensitivity, inductive language learning ability and rote learning ability. The correlation of each component with pre-service language teachers’ achievement levels is analyzed.

Firstly, when we look at the correlation between pre-service language teachers’ phonetic coding ability and their English achievement levels, it is clear that there is a slight correlation (r = .30) as shown in Table 2.

Secondly, it was found that there is a moderate correlation (r = .39) between pre-service language teachers’ grammatical sensitivity and their L2 achievement as seen in Table 3.

Thirdly, results showed that there is a moderate correlation (r = .53) between pre-service language teachers’ inductive language learning ability and their English achievement level as shown in Table 4.

Therefore, in the view of such findings the ability of pre-service language teachers to learn the forms and meanings of linguistic patterns implies that they will get a high score in English tests.

Lastly, it was found that there is a weak correlation (r = .23) between pre-service language teachers’ rote learning ability and their English achievement level as shown in Table 5.

According to the findings, pre-service language teachers’ English scores are dependent on their ability to notice and process linguistic patterns during the learning process, so pre-service language teachers’ rote language learning ability is a predictor of their success in English.

When we look at the overall correlation between pre-service language teachers’ language aptitude and their English achievement levels, it is clear that there is a slight correlation (0.35) as shown in Table 6.

It can be said that there is not a strong linear relationship of language aptitude with pre-service language teachers’ achievement levels, so aptitude test is not an appropriate way to predict English achievement of the pre-service language teachers. Moreover, there can be other mediating factors such as motivation, anxiety and self- regulation which affect the correlation between pre-service language teachers’ language aptitude and their English achievement levels.