Main project

Our project will chart variability in child speech for a range of speech measures that reflect the functioning of the four speech subsystems – respiration, phonation, resonance and articulation. Using a longitudinal approach, we will determine the developmental trajectories of child speech for each subsystem and establish to what extent development in one subsystem predicts development in the others.

Research objectives:

  •  to collect, annotate and analyse speech data from a large cohort of primary school children across Scotland every 6 months over 1.5 years.
  • use this data to determine the range and patterns of variability in child speech for standard speech measures across the four speech subsystems.

What does taking part in the research involve?

We are inviting all children attending P1, P3 and P5 in Scotland to participate in this project, which involves collecting speech recordings from children in these age groups. A specifically designed app will move through a series of speech activities including a story retelling task, a picture description, a word naming and sentence repetition task, and lastly, tasks that test the oro-motor functioning in children.


The subproject focuses only on one subsystem: articulation. We will use an ultrasound machine to look at the tongue during speech. In this technique, an ultrasound probe is placed under the chin, imaging the tongue moving in real time. Previous analysis of ultrasound images show that children with Speech Sound Disorders (SSDs) can produce unusual and variable tongue shapes (Sugden & Cleland, 2021).  However, we do not yet understand how variable typically developing children are due to a lack of evidence. This subproject will collect these recordings from typically developing children, to see how variable their tongue shapes are at different ages and over time as they grow.

Research objectives:

  • collect data from 40-60 primary school children in Scotland every six months over one year
  • Use this data to determine variability in lingual articulation in typically developing children over time

Look-up facility

At the end of the project, derived data will be made open-access to create an online look-up facility on this website. This facility can be used by speech and language therapists as a baseline reference of typical variation in children’s speech when diagnosing and treating children with speech and voice disorders.


The research team will engage in various activities throughout the duration of the project to disseminate our findings and share resources. These will include publications and presentations at conferences, public engagement events, regular blog updates cataloguing the project’s milestones. Keep an eye on our News section for the latest developments.