INTRODUCTIONThe concept that highlights the adjustments native speakers employ in conversations has been mentioned in literary works of long time ago such as in C.S. Lewis' novel, Out of the Silent Planet. It was then Charles Ferguson who coined the term "foreigner talk" in 1969. He defined FT as one of the varieties of simplified speech which is used by native speakers when talking to foreigners. Foreigner talk is commonly regarded in a given speech community as an imitation of the way foreigners speak the language under certain conditions, and it is usually elicited more readily by asking for this kind of imitation than by asking the informant how he would speak to a foreigner (Ferguson, 1975).What makes foreigner talk a simplified speech is a question on the quality of input native speakers provide for the nonnative interactor. Such phenomenon requires certain modifications intended to make the conversation simple and easy to comprehend on the part of the Nonnative Speaker. Hence, when speaking to NNSs (Nonnative Speakers), the NSs (Native Speakers) may speak more slowly, pronounce every word clearly, and use short sentences and basic vocabulary. Research has to guarantee, therefore, that foreigner talk or linguistic simplicity, amounts to cognitive simplicity, or the question of how FT aids comprehension of nonnative hearers must be made clear.According to Ellis (2009), the characteristics of foreigner talk are very similar to those found in other simplified registers such as learner language, caretaker talk, and pidgins. This suggests that FT reflects universal processes of simplification, knowledge of which constitutes part of a speaker's linguistic competence. On a relative note, Hatch (1983) considered three ways in describing foreigner talk;(1) regression (native speakers move back through the stages of development that characterized their own ABSTRACT This critical review of literature provides a detailed description of foreigner talk as a simplified register and critically discusses findings entrenched in studies done about this SLA issue. The studies cited are classified as researches concerning foreigner talk that occurs in both natural and classroom settings. Based on the critical review, more research investigations have to be done to enrich the area of foreigner talk in second language acquisition and learning. The most important consideration is the need to conduct more researches that would validate both the positive and negative effects of foreigner talk in the process of acquiring and learning a second language as well as a foreign language like English. The emergence of significant concerns on the study of FT is also highlighted in this presentation which include how researchers regarded the effectiveness of both input modifications and interactional adjustments along with the occurrence of negotiation of meaning and the use of communication strategies in the SLA process. The paper also presents empirical data on the effectiveness of NNS-NNS interactions in second language learning in contras...