The project reported in this book was initiated about three decades ago in the early 1990s. Developed from the Frank Porter Graham study (FPG), a project originally focusing on medical issues, this study tracked and analyzed the language development of eighty-eight young African American speakers in North Carolina for the first twenty-one years of their lives.

This book consists of nine chapters. The first chapter briefly outlines how the study grew out of the FPG project, as well as identifying and commenting on the desirable properties of this longitudinal study (see below). Chapter 2 lays the methodological foundation for analyses found in subsequent chapters. It especially introduces in detail a main composite index that is studied as dependent in chapters 5–7 and independent variable in chapter 8—the Dialect Density Measure (DDM). It is a token-based composite index which provides a holistic score of a speaker's vernacular dialect use by measuring the number of AAL features per communication unit. The next six chapters report studies that explore the relationship between AAL use in young speakers and several variables of interest. Among these variables are age, gender, school demographics, home environment, vowel shifts in the broader region, the speech style of caregivers and peers, formality of the situation, and literacy skills.

Importantly, this book presents the first large-scale longitudinal study on the early language development of AAL speakers. From having longitudinal data of AAL speakers, the researchers have been able to ask questions that would not have been possible with cross-sectional or real-time case study data, the type of data most common for studies of AAL. For example, multiple hypotheses exist as to when AAL use increases or decreases at certain time points in the early lifespan, and the longitudinal nature of the data has allowed the researchers to connect these time points, presenting a more complete developmental trajectory. I would be remiss not to mention the benefit from the scale of this study as well. Compared with case studies, where there is only a small number of subjects, the large sample in this study enables sociolinguists to clearly see the depth of individual variation among speakers of AAL. For instance, while the predominant pattern showed a decrease in AAL usage at around six to nine years old and another in early adulthood as previously hypothesized, trajectories that had not been hypothesized were found as well, such as stable patterns throughout the duration of the study.

In an era when open science is more accessible, this study would have even more value if its speech data were made publicly available; nonetheless, it is replication-friendly by its detailed explication of its methods and analysis. Experienced AAL researchers may find insights in the novel data and inspiration in the analyses performed by the researchers. Newcomer researchers in the field will benefit from the clarity in the methodology, allowing for potentially helpful replication studies to be conducted, even if not on as large a scale as this one.