Applied linguistics, including psycholinguistics, has its roots in psychological research (see Wundt’s lab, the works of Skinner, Sapir and Whorf, etc.) so we may rightly ask whether linguists should incorporate the results of psychology about memory into their own research or simply ignore them. Psychological theories have faced a lot of skepticism in language attrition research (e. g. Weltens, 1987) which can be due to the fact that language forgetting was hardly addressed by these theories. To understand forgetting, we must first examine the components of memory. Memory processes work depending on how long we want to store an item: less than 1 second, a few seconds, minutes, hours, years. Based on this, we distinguish 3 memory stores: 1. the sensory store, where information is stored for a maximum of a few seconds and from there it is selectively transferred to short-term memory; 2. short-term memory or working memory, where we are able to store a limited number of items for a short time and which also plays a role in retrieving information; 3. long-term memory with an infinite capacity where we reserve memories. (Atkinson et al., 2005) Short-term and long-term memory have three functions: encoding (placement in memory), storing (keeping in memory), retrieval (retrieving from memory). (Melton, 1963) If we consider the effects of the second language on the first it is clear that the encoding phase is intact, „forgetting” indicates the failure of storing or retrieval. (Ecke, 2004)