Thus, language is “so uniquely human, distinguishes us so clearly from other animals, that our species might be more appropriately named homo loquens than homo sapiens” (Widdowson, 1996: 4), especially so that language is innate in man.
With man’s birth is the natural tendency to acquire and master a language as he/she grows, making language essential to man’s existence as it is his/her most effective means to communicate, build relationships, and form societies. With man’s experiences, beliefs, feelings, etc. expressed in the complex system of symbols, language defines man. the language man speaks in return speaks for the speaker him/herself. Hence, “when we study human language, we are approaching what some might call the ‘human essence’, the distinctive qualities of mind that are, so far as we know, unique to man” (Chomsky, cited in Fromkin & Rodman, 1998: 3). In fact, the study of language has been historically centred on the study of the nature of the human mind and thinking, as it has long been believed that being distinct to man, “languages are the best mirror of the human mind” (Leibnitz, cited in Chomsky, 1986: 1).
In this context, the study of language becomes not only important but fascinating, too, as it deals with one of the most mysterious endowments of man that a plethora of research studies and theories abound, yet until now, more and more questions are left unresolved. One area in language study that attracts further inquiry is language acquisition. As Leonard Bloomfield (1933: 29), said: “the acquisition of language is doubtless the greatest intellectual feat anyone of us is ever required to perform”. If the acquisition of first language in early childhood raises many questions, the acquisition of second language by older children and adults raises more questions, especially in relation to FLA.