The present study investigates the nature of communicative language ability as manifested in performance on the TOEFL iBT® test, as well as the relationship between this ability with test-takers' study-abroad and learning experiences. The research interest in the nature of language ability is shared by the language testing community, whereas understanding the factors that affect language acquisition has been a focus of attention in the field of second language acquisition (Bachman & Cohen, 1998). This study utilizes a structural equation modeling approach, a hybrid of factor analysis and path analysis, to address issues at the interface between language testing and second language acquisition. The purpose of this study is two-fold. The first has a linguistic focus: to provide empirical evidence to enhance our understanding of the nature of communicative language ability by examining the dimensionality of this construct in both its absolute and relative senses. The second purpose, which has a social and cultural orientation, is to investigate the possible educational, social, and cultural influences on the acquisition of English as a foreign language, and the relationships between test performance and test-taker characteristics. The results revealed that the ability measured by the test was predominantly skill-oriented. The role of the context of language use in defining communicative language ability could not be confirmed due to a lack of empirical evidence. As elicited by the test, this ability was found to have equivalent underlying representations in two groups of test-takers with different context-of-learning experiences. The common belief in the superiority of the study-abroad environment over learning in the home country could not be upheld. Furthermore, both study-abroad and home-country learning were proved to have significant associations with aspects of the language ability, although the results also suggested that variables other than the ones specified in the models may have had an impact on the development of the ability being investigated. From a test validation point of view, the results of this study provide crucial validity evidence regarding the test's internal structure, this structure's generalizability across subgroups of test-takers, as well as its external relationships with relevant test-taker characteristics. Such a validity inquiry contributes to our understanding of what constitutes the test construct, and how this construct interacts with the individual and socio-cultural variables of foreign language learners and test-takers.

This dissertation concerns oral language tests from a grammatical perspective. Tests today are usually assessed based on a communicative approach to language, so it is interesting to see how great a significance the level of grammatical development of test takers has for their communicative competence in general. The data in the investigation consist of recorded test conversations from a Swedish national language proficiency test, Tisus (test in Swedish for university and university college studies). The general aim of the study is to investigate whether there is a difference between the test takers who passed and those who failed in terms of their level of grammatical development. This is investigated in one main study and two smaller follow-up studies. The theoretical basis for this work is comprised of theories on second language learning and theories on language testing. For the grammatical analysis, Pienemann’s processability theory (PT) is applied. This theory posits that learners acquire certain morpho-syntactic structures in a particular order, something that produces a hierarchy consisting of five levels. In the main study, a quantitative analysis is made of the test takers’ level of grammatical development relative to their TISUS results. The results show a clear correlation between grammatical level and test results. There also seems to be a kind of watershed at level 4, given that most of the test takers who passed have command of this level in the PT hierarchy, whereas those who failed, as a rule, only make it to level 3. The first follow-up study is more qualitative in nature and is focused on the test takers who deviate from the general pattern of results in the main study: those who failed despite their high grammatical level and those who passed despite their low grammatical level. One result of this follow-up study is that, in these cases, it appears communicative competence was critical. Being able to orient oneself to the special conversational situation represented by the test conversation is considered to be particularly important. In a second follow-up study, the problems of applying PT to morphology and syntax are examined. The results of the dissertation suggest that there is a correlation between grammatical competence and communicative competence in general. This means that the grammatical levels in the PT hierarchy may constitute a useful basis of analysis in oral assessments, as a complement to other assessment tools.