title: Assessment of intelligibility using children's spontaneous speech: methodological aspects.
abstract: BACKGROUND
  Intelligibility is a speaker's ability to convey a message to a listener. Including an assessment of intelligibility is essential in both research and clinical work relating to individuals with communication disorders due to speech impairment. Assessment of the intelligibility of spontaneous speech can be used as an overall indicator of the severity of a speech disorder. There is a lack of methods for measuring intelligibility on the basis of spontaneous speech.
  
  
  OBJECTIVE
  To investigate the validity and reliability of a method where listeners transcribe understandable words and an intelligibility score is calculated on the basis of the percentage of syllables perceived as understood.
  
  
  METHODS
  Spontaneous speech from ten children with speech-sound disorders (mean age = 6.0 years) and ten children with typical speech and language development (mean age = 5.9 years) was recorded and presented to 20 listeners. Results were compared between the two groups and correlation with percentage of consonants correct (PCC) was examined.
  
  
  RESULTS
  The intelligibility scores obtained correlated with PCC in single words and differed significantly between the two groups, indicating high validity. Inter-judge reliability, analysed using intra-class correlation (ICC), was excellent in terms of the average measure for several listeners.
  
  
  CONCLUSIONS
  The results suggest that this method can be recommended for assessing intelligibility, especially if the mean across several listeners is used. It could also be used in clinical settings when evaluating intelligibility over time, provided that the same listener makes the assessments.
authors.affiliation: The Sahlgrenska Academy at the University of Gothenburg, Institute of Neuroscience and Physiology, Division of Speech and Language Pathology, Gothenburg, Sweden.
authors.forename: Tove B
authors.initials: TB
authors.lastname: Lagerberg
authors.forename: Jakob
authors.initials: J
authors.lastname: Åsberg
authors.forename: Lena
authors.initials: L
authors.lastname: Hartelius
authors.forename: Christina
authors.initials: C
authors.lastname: Persson
mesh_terms: D002648:Child; D002663:Child Language; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007805:Language Development Disorders / Q000175:diagnosis*; D008297:Male; D010700:Phonetics; D015203:Reproducibility of Results; D013060:Speech; D013064:Speech Disorders / Q000175:diagnosis*; D013065:Speech Intelligibility; D013068:Speech Production Measurement / Q000379:methods* / Q000592:standards*
keywords: PCC; children; continuous speech; intelligibility; speech disorder; spontaneous speech