Treatment generalization from trained /ɹ/ to untrained /l/: a case study of persisting distortion errors

Caitlin Raaz, Megan C. Leece, Tara McAllister, Jonathan L. Preston

Research output: Contribution to journalComment/debatepeer-review


The extent to which treatment of speech errors that are phonetic in nature (i.e., distortions) produces generalization to untrained sounds is not well understood. This case study reports a child referred for treatment of a velarized distortion of American English /ɹ/, who also demonstrated an inconsistent velarized distortion of /l/. Acoustic analysis revealed evidence of a covert contrast between /ɹ/ and /l/ prior to treatment. Ultrasound biofeedback treatment and perceptual training targeted /ɹ/ only, but progress was tracked for both /ɹ/ and /l/. Substantial improvements in perceptually rated accuracy and significant changes in acoustic features were observed for both sounds, indicating generalization. These results highlight that generalization from trained to untrained sounds is possible for children with residual speech errors characterized by phonetic distortions.

Original languageEnglish (US)
Pages (from-to)1210-1219
Number of pages10
JournalClinical Linguistics and Phonetics
Issue number12
StatePublished - 2021


  • Speech sound disorders
  • covert contrast
  • generalization
  • rhotics

ASJC Scopus subject areas

  • Language and Linguistics
  • Linguistics and Language
  • Speech and Hearing


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