The theory of competency vs. Proficiency was first created by Noam Chomsky who was a cognitive psychologist. He studied linguistics extensively, and contributed greatly to the ideas of modern psychology through his studies in understanding mental processing and human nature. This theory states that competency is a person’s ideal image of the understanding of the language, and specifically the rules and grammar. However when someone is competent in language, it is not the same as if someone was proficient. Proficiency refers to the ability to use the language in real life, and different varieties of tasks. However there are still other theories, such as communitive competence. This theory was first thought of by Ell Hymes, and is more a bridge between the two because it includes more in the idea of competency. Chomsky described competency to be purely grammatical, Hymes described it to include all types of knowledge that a learner would need to communicate effectively.
The measurement of language acquisition is difficult to establish, but also necessary. There are many tests available for measuring SLA, for example the TOEFL (test of English as a foreign language), KLPT (Korean language proficiency test), TEF (Test d’evaluation du francias), and CET (college English test). These types of assessments attempt to measure proficiency and competency. Competency is measured by sections in the test such as grammar, writing, and reading. Proficiency can be tested by speaking and listening sections. Others believe second language acquisition can be measured by what stage of language development the person is in. However the stages of language acquisition are mostly centered on proficiency. The first stage is the silent stage, and the last stage is advanced fluency. This does not take into consideration the competency of the student.