Jaime Ross Maldonado. Michael Ruiz Troncoso. Summary Ernest Macaro acknowledges the differences between First language (L1) and Second language (L2) have made Second language Acquisition an independent discipline, and its Ideas and research techniques different for both. On one hand, research ideas from L1 acquisition, Brown and McNeil emerged SLA research applying the independent grammar assumption on children’s language, and pointed out that children language system is different to adult’s, focusing on the learner’s language system. On the other hand, SLA research took some research techniques from L1 acquisition. Such as the natural data’ (Cook, 1986), which are techniques for studying sentences, and the ‘Error Analysis (EA)’ (Corder, 1971), which looked at the differences between the learners’ speech. Moreover, there are different L1 acquisition theories and L2 acquisition. ‘The theory of mind’ Tomasello (2003), with two main components: intention-reading and pattern finding. Also, the social theories of language by Halliday. ‘Language is for doing things and for relating to people’. Halliday (1975) children’s express in terms of functions such as: the interpersonal (relating to people), the ideational (communicating ideas to other people) and the textual (relating one piece of language to another).Besides, Chomsky and his theory of universal grammar has always been concerned of syntax’s acquisition, but also he points out that children always manage to learn language, no matter their situation. Finally, there exist differences and similarities between first and SLA. Some differences are the age of L2 learners who are mostly adults, and L1 learners (children). Another difference is the lack of another language in the L1 child’s mind. L2 learners already have an L1 in their minds, “everything the learner acquires and does involves both first and second languages”. Furthermore, the comparative maturity of the L2 learner is another difference. L2 learners are more mature than L1 child and has different advantages of memory, conceptual and social development, and command of speech styles. Jaime Ross Maldonado. Michael Ruiz Troncoso. Evaluation Ernest Macaro shows different aspects in his text, using a huge variety of viewpoints to add in, and give truthfulness to his arguments. Brown and Chomsky are ones of the most important exponents in this subject, no offense intended that he uses to make sense of what it propounds with respect to studies, techniques and theories in Second Language acquisition research. Regarding to the interpretation of the text, there is no room for doubt that it is an objective and realistic method to set up in a clear and accurate way the relationship between L1 and L2 acquisition. The quality of his reasoning is felt in every word, line and paragraph of the text, because he writes approaching unconditionally to the real facts in the learning process, instead of see what he wants to see, which besides is a thing that much people do to get something to write about. Taking the facts as he does, the text turns to be interesting to people that is concerned about this topic. However, the text is not directed to everyone, because even when someone looks at it as an important matter, there is another group of people who are not concerned about it, or simply they feel that this field of study is not directed to them. In addition, about what was previously written, would be a fault that this was not directed to every kind of people, although is the responsibility of the author to make a text readable for everyone. However, he (in this case) cannot turn around to people’s interest who are not feeling related to the topic, he needs to convince the reader in order to make the test more interesting and easy to read. In general lines, the knowledge and accuracy that the text has, as said before; makes impossible to discover any kind of mistake. Moreover, it ends up convincing the reader, in accordance with all the ideas expressed, and those who do not want to realize that there are structures in the process of language acquisition, in other words, those who ignore how necessary is L1 to the acquire L2, just to mention the relationship between both of them. Consequently, if someone says that the text is wonderful and likable, it would not be significant, because a personal opinion does not work when it has been dealing a real fact, and less if this opinion is about personal feelings. There are certain types of topics in the text which create certain kind of questions, but it is not because of the lack of information, rather the opposite; there is a lot of information which is expressed very clearly, and it makes you wonder yourself things like: What would happen if you lose your memory in a country where your Second Language (L2) is seen as your First language (L1)? What will happen with your L1? Maybe you are going to forget it or maybe not, is it possible that your L2 turn into your L1? These are some of the question that encourages many readers to look for more information. Jaime Ross Maldonado. Michael Ruiz Troncoso. References Macaro, E. (2010). The Continuum Companion to Second Language Acquisition. London: Continuum.