Introduction: Within the field of speech-language pathology, many assume commonly used informal speech sound measures are reliable. However, lack of scientific evidence to support this assumption is problematic. Speech-language pathologists often use informal speech sound analyses for establishing baseline behaviors from which therapeutic progress can be measured. Few researchers have examined the test-retest reliability of informal phonological measures when evaluating the speech productions of young children. Clinically, data regarding these measures are critical for facilitating evidence-based decision making for speech-language assessment and treatment.
Objectives: The aim of the present study was to identify the evidence-base regarding temporal reliability of two such informal speech sound measures, phonetic inventory and word shape analysis, with two-year-old children.
Methods: The researchers examined analyses conducted from conversational speech samples taken exactly one week apart for three children 29- to 33-months of age. The videotaped 20-minute play-based conversational samples were completed while the children interacted with their mothers. The samples were then transcribed using the International Phonetic Alphabet (IPA) and analyzed using the two informal measures noted above.
Results: Based on visual inspection of the data, the test-retest reliability of initial consonant and consonant cluster productions was unstable between the two conversational samples. However, phonetic inventories for final consonants and word shape analyses were relatively stable over time.
Conclusion: Although more data is needed, the results of this study indicate that academic faculty, clinical educators, and practicing speech-language pathologists should be cautious when interpreting informal speech sound analyses based on play-based communication samples of young children.