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The Vocal Development Landmarks Interview Helps Clinicians and Families Track Vocal Developmental Milestones


Wednesday, September 18, 2019


Monitoring how babies progress through the early stages of vocal development is important for professionals and families, especially when infants have developmental challenges, such as cerebral palsy, hearing loss, down syndrome, cleft palate, or other special needs. It is essential that children who are at risk for speech and language delays are identified as early as possible so interventions can be tailored to minimize developmental risk. Drs. Mary Pat Moller and Sophie Ambrose at Boys Town National Research Hospital, along with Dr. Anne Thomas of the University of Nebraska-Lincoln, developed the Vocal Development Landmarks Interview (VDLI) for this purpose.

They recognized that the best way for professionals to monitor an infants' vocal development is to ask the parents about the child's vocal productions. However, they also realized that a better tool was needed to allow professionals to do that. The VDLI is a parent-report instrument for infants and young children who are not developmentally ready to cooperate with more structured testing [1]. It incorporates what has been learned from years of laboratory-based observations about the orderly stages of vocal development that babies go through and involves parents as the best resource for understanding if their child is meeting these vocal milestones.

The VDLI design uses a series of digital slides with audio files containing authentic infant vocalizations to ensure parents know exactly what vocal behavior the professional is asking them to report on. The vocal behaviors are also arranged in developmental order, beginning with those typically observed by 6 months of age and ending with those typically observed by 21 months of age.

According to Dr. Ambrose, “The feedback we've gotten is that the tool really helps both parents and clinicians learn about behaviors to watch for and which behaviors to encourage the development of next in early intervention." She also indicated that clinicians reported wanting a tool that was easy to use with families in homes, which led the team to collaborate with the Technology Core at Boys Town National Research Hospital to create the VDLI as an iOS App that allows for maximum accessibility and portability. For more information on the VDLI, watch the included video in this article or access their recent publication cited below. For help with downloading the app and its related resources, you can contact Dr. Ambrose at


  1. Moeller, M. P., Thomas, A. E., Oleson, J., & Ambrose, S. E. (2019). Validation of a parent report tool for monitoring early vocal stages in infants. Journal of Speech, Language, and Hearing Research, 62(7), 2245–​2257.