Research shows many problems and ambiguities of second language acquisition (SLA), which have made learners and readers worldwide unsatisfied. Therefore, this study attempts to highlight theories and research that have comprehensive explanations of the problems and ambiguities of second language acquisition, which learners of English as a Foreign Language (EFL) face while learning a second or foreign language. After that, the study discusses a framework discussion on second language acquisition (SLA). It discusses the historical background of SLA research on different decades and the most notable views of different scholars throughout the past decades on second language acquisition. This study is a longitudinal research that identifies the advantages that could be an assist to English as Foreign Language (EFL) learners. Longitudinal research is always based on the qualitative method. This study's data is based on the qualitative method that collects views, opinions, materials, and earlier studies on second language acquisition (SLA). It reveals the most significant theories which precisely connected to second language acquisition (SLA) and largely to applied linguistics. The study resulted in that: (1) second language acquisition still has several doubts and ambiguities in its many different aspects; and (2) in this study, the researcher summarizes second language acquisition (SLA) research's main goals and draws comparisons on the scholars' dissimilarities between language learning and second language acquisition (SLA) on different perceptions that could give insights towards learning of second and foreign languages easily by the English as Foreign Language (EFL) learners.