The study of second language acquisition through the analysis of the language learners mental process and strategies seeing how researchers investigate on language learning and processing;how they collect the data;which factors,mechanisms and processes they examine for constracting and testing theories.The exploration of human mind following the cognitive psychology theories applying to the Multi-store memory model (Atkinsons and Shiffrin) and the Working memory model (Baddeley) in connection with the relationship between memory and language,trying to understand also the implication in quotidian actions of words temporary memory.A look on the links between memory and attention demonstrated by the Cowan’s Embedded-processes model of working memory,showing how memory and attention are involved in language acquisition.The attempt is the comprehension of the way in which learners acquire a second language ,how they develop their linguistic and communicative competences and in which processes are involved in. Introduction It is not possible to do a direct inspection on the learners mental knowledge.This can only be inferred by examining samples of the learners performance.Second language researchers have used different kinds of performance to try to investigate competence.Very different results can be obtained depending on the kind of performance data the researcher studies.Researchers disagree about what kind of performance they think provides the best evidence of acquisition.It is impostant to examine carefully the nature of the data used and the way in which acquisition has been measured,in reading reports of actual studies.The goal of second language researchers is the description and the explanation of the learners’linguistic and communicative competence.The study of how learners learn a second language does not have a very old story (the surge of empirical work that inform current thinking did not begin until the late 1960s).The study of learners-external factors and learner-internal mechanisms constitutes an attempt to how second language acquisition takes place (learner-internal mechanisms concern on how learners use their resources in communication and on how they acquire the language,these mechanisms are mental and largely hidden from view althuoght not necessarly completely unconscious).Then there is the question of individual learners differences and what causes them.Learners set about the task of acquiring a second language in different ways.They differ with regard to such general factors as motivation and aptitude,and also in the use of various strategies for obtaining input and for learning from it.he study of these general factors and on the learning strategies helps to explain why some learners more and more rapidly than others and why they reach higher level of proficiency.Learners language study is the starting point of the exploration of second language acquisition because it provides the data for constructing and testing theories of second language acquisition (analysis of errors,acquisition orders and developmental sequences,variability,pragmatics aspects,study of input and interaction,analysis of discourse). 1-Theories and memory models Since the early 20th century various schools of psychology attempted to develop learning theories.Every school developed different theories working on distinct perspectives of human mind.The first was the behaviourist psychology school.For the behaviourism movement the human mind was totally unknowable.This school maintains that only the behaviour can be observed and analysed scientifically.Even the language learnig process is seen as a behaviour (verbal behaviour).The behaviourist theory affirms that language is a product of habit and it can be acquired by conditioning through a stimulus-response mechanism (external stimuli activate responses to the exactly for the animals).The empirical work so is concentrated only on the observable phenomens and processes (external factors).In 1960s Cognitivism replaced behaviours becoming the dominant paradigm.The cognitive psychologists look at the learners as information processors (like a computer).Focusing on the inner mental activities to understand how people learn,mental processes as thinking,memorising,knowing and problem-solving have to be explored.For cognitivists human mind can be seen as a computer where information comes in,it is being processed and leads to certain outcomes.The cognitive approach on the information processing has provided psycholinguistics with the means for anlysing how the learners process the language,cognitive theories have given a revolutionary contribution to linguistics.The assumptions are that for processing information there are two separated channels,associated with the different senses,auditory and visual (with two dinstinct sensory stores the echoic memory and the iconic memory);each channel has a limitated capacity,learning is an active process where information is being filtrate,selected,organized and integrated on the basis of prior knowledge.In 1968 Atkinsons and Shiffrin proposed a model of human memory which explains the human information processing system.They despribed a three-store model indicating three different memory systems:sensory memory,short-term memory (STM) and long-term memory (LTM).Human mind has a limited capacity for the amount and the nature of information it can process.An invironmental stimulus activates our senses (information can be just processed in a channel at a time).Incoming information enters the information processing system,the trace of t>