The term second language refers to any language other than one's mother tongue. The second language acquisition theory describes the different phases of the process of language acquisition. It refers to the study of how and through what process an individual acquires a second language. One faces difficulties while learning a second language as the process of learning is often hindered by the knowledge of one's first language. Every language has its own set of rules for grammar, syntax, and pronunciation. The knowledge of these rules obstacles one's process of understanding the rules of a non-native language. However, research also says that one's cognitive development in his/her native language helps the person transfer the already learned concepts to the second language. The basic concepts and ideas of one language can be suitably applied to any other language. Thus, knowing one language is definitely helpful in learning another. One's learning of a second language is affected by his/her exposure to language models. Second language acquisition is also affected by one's emotional state. Students often experience fear and anxiety before learning a new language. At times, they lack the motivation to learn it. The social and cultural values of students and their beliefs have a direct effect on second language acquisition. The process of second language acquisition is divided into four identifiable stages of learning. Stage I: Silent Stage This stage can last from about 10 hours to 6 months. During this stage, though the students do not acquire the ability to speak the language, they are able to respond to new words and pronunciations. This is a stage of understanding new words as well as their meanings and pronunciations. Students are often observed as being able to gesture or respond with a 'yes' or 'no', during this stage of language acquisition. During this phase of learning, the students face what is known as a language shock and are seen rejecting the words of the second language that do not make meaning to the learner. Though the learners do not speak during this phase of acquisition, they are observed to be engaging in self-talk. Stage II: Early Production During this phase that lasts for about 6 months, the learners develop an understanding of about 1,000 active words. During this phase of language acquisition, learners gain the ability to speak a few words and use some simple phrases of the language. Mispronunciations are the common mistakes that learners make, during this stage of second language acquisition. It is important for the teachers to introduce the students to new words in the second language, thus helping them enhance their second language vocabulary. Stage III: Emergence of Speech The learners who had been receiving words and giving simplistic responses during the previous stages, begin to speak in their second language during this phase. The students start forming simple statements, improve pronunciation and take a few steps towards reading and writing in the second language. Students try to form big sentences and tend to make mistakes in the grammatical structuring of the sentences. It is important that the teachers encourage greater usage of words, and see to it that students are taking an initiative in conversing in the second language. Stage IV: Intermediate Ability This phase can last for one year after speech emergence. It involves the usage of complex sentences and attempts to use the newly acquired language to a greater extent. This stage is about attaining a certain level of proficiency wherein they can opine, discuss and most importantly begin to think in the second language. Even after a student is proficient in conversing in a particular language, his/her ability to think in a non-native language is an entirely different skill the learner needs to acquire. Stage V: Advanced Fluency It takes a couple of years to gain complete proficiency in a non-native language. A completely new language that the students have learned takes time to get fully absorbed into their minds. It takes a few years for the students to gain the abilities of fluent conversation and clear thinking in their second language. This stage involves development of a separate vocabulary of that language and the achievement of a confidence in expressing oneself by means of the second language. Though second language acquisition theoretically ends at the fifth stage, the enhancement of language skills and expansion of the vocabulary is a continuous process. In its true sense, the process of learning a language never ends.