This article explores the linguistic profiles of heritage speakers of Russian and Spanish. Data from the 2009-2013 ACTFL-UCLA NHLRC Heritage Language Project included biographical information as well as speech samples that were elicited using the ACTFL Oral Proficiency Interview-computer and were rated according to the ACTFL Proficiency Guidelines 2012-Speaking by certified testers. The goal of the study was to better understand the multiple linguistic, educational, and experiential factors that contributed to the speaking proficiency of these heritage speakers as well as how those features affected the tasks and contexts in which the speakers could more appropriately communicate in the language. The data illuminate the linguistic strengths and weaknesses of speakers within certain ranges and highlight those language features that prevented the participants from being rated at the next higher level. The authors discuss implications for teaching and learning and make recommendations for both heritage speakers and their instructors.