The impact of real-time articulatory information on phonetic transcription: Ultrasound-aided transcription in cleft lip and palate speech

Abstract

Objective: This study investigated whether adding an additional modality, namely ultrasound tongue imaging, to perception-based phonetic transcription impacted on the identification of compensatory articulations and on interrater reliability. Patients and Methods: Thirty-nine English-speaking children aged 3 to 12 with cleft lip and palate (CLP) were recorded producing repetitions of /aCa/ for all places of articulation with simultaneous audio and probe-stabilised ultrasound. Three types of transcriptions were performed: 1. Descriptive observations from the live ultrasound by the clinician recording the data; 2. Ultrasound-aided transcription by two ultrasound-trained clinicians; and 3. Traditional phonetic transcription by two CLP specialists from audio recording. We compared the number of consonants identified as in error by each transcriber and then classified errors into eight different subcategories. Results: Both the ultrasound-aided and traditional transcriptions yielded similar error-detection rates, however these were significantly higher than the observations recorded live in the clinic. Interrater reliability for the ultrasound transcribers was substantial (k=0.65), compared to moderate (k=0.47) for the traditional transcribers. Ultrasound-aided transcribers were more likely to identify covert errors such as double articulations and retroflexion than the audio-only transcribers. Conclusion: Ultrasound-tongue imaging is a useful complement to traditional phonetic transcription for CLP speech.