This book explores the social construction of age in the context of EFL in Mexico. It is the first book to address the age factor in SLA from a social perspective. Based on research carried out at a public university in Mexico, it investigates how adults of different ages experience learning a new language and how they enact their age identities as language learners. By approaching the topic from a social constructionist perspective and in light of recent work in sociolinguistics and cultural studies, it broadens the current second language acquisition focus on age as a fixed biological or chronological variable to encompass its social dimensions. What emerges is a more complex and nuanced understanding of age as it intersects with language learning in a way that links it fundamentally to other social phenomena, such as gender, ethnicity and social class.