This chapter focuses on identifying anxious language learners, a critical first step for instructors seeking to support students experiencing foreign language anxiety (FLA). While a variety of FLA scales exist and can be employed to identify such learners, it is not feasible to expect language instructors to routinely administer these instruments in everyday classroom practice. Therefore, it is essential for foreign language (FL) instructors to become familiar with the observable manifestations of FLA, which can be categorized into five dimensions: physical, cognitive, psychological, communicative, and behavioral. Despite the pedagogical relevance of this approach, empirical research investigating the use of these manifestations as diagnostic tools remains limited. Notably, Gregersen’s series of studies employed observational research paradigms to compare anxious and non-anxious learners’ responses to errors and nonverbal behavior in anxiety-inducing situations, yielding valuable insights for classroom identification and intervention.