This article aims to show and explain the growing motivational, personal or affective difficulties that unemployed adult learners are currently facing in the English subject when they decide to retake their education in age-diverse Vocational Training Programs in the Spanish educational system. The results presented in this article are based on a multiple case qualitative study research directed in two different areas. The participants were vocational training teachers who participated in a semi-structured interview. They confirmed the increasing level of frustration and dropout rate that Spanish adult students are experiencing in the L2 subject of these programs, mostly due to their oral and comprehension skills. The results of this article show the numerous obstacles of adaptation to the L2 contents and methodologies that adult learners face; generally because they are surrounded by adolescent or younger classmates who have more experience in the foreign language and a wider linguistic knowledge. It is further explained how this age heterogeneity in the English classroom leads to difficulties in the linguistic acquisition, lack of adaptation to current L2 teaching methodologies and lack of inclusion in the rest of the group, due to motivational limitations derived from fear of ridicule, self-imposed affective barriers and anxiety in the English classroom.