The present study attempted to investigate if alaryngeal speakers of Mandarin Chinese could differentially produce the four tone levels of Mandarin: high-level, mid-rising, falling-rising and high-falling, as perceived by native listeners. Syllables /ma/ and /ba/ produced at four different tone levels by 8 normal laryngeal (NL), 7 standard esophageal (SE), and 8 electrolaryngeal (EL) speakers of Mandarin were perceived by 8 naïve listeners. Results from the listening experiments showed a higher percent correct identification of tone for NL speech than SE and EL speech. Perceptual data showed different patterns of tone confusion associated with the three types of speech. SE and EL speakers were not able to produce the four tone levels as accurately as were NL speakers. NL speakers achieved a near-perfect level of accuracy in signaling tonal contrasts. SE speakers produced the falling-rising and high-falling tones more accurately than high-level and mid-rising tones, but tonal confusions existed between mid-rising tone and falling-rising tone, and between high-level tone and high-falling tone. In EL phonation, high-level tone was produced more accurately than the other tones which were often misidentified as a high-level tone.

Objective: To improve the speech quality of laryngectomized speakers of Mandarin, we designed an electrolarynx with tonal control function (tone-EL) by using the movement of a trackball. The performance of the tone-EL in producing Mandarin was evaluated. Methods: The performance of tone-EL was evaluated via a listening experiment. The perceptual accuracies of monosyllabic words, different categories of phrases with different cues were measured and compared with that produced with a conventional EL. The acceptability of sentences was also measured. Results: The perceptual accuracies of monosyllabic words and tones associated with the words produced with the tone-EL were significantly higher than those of monotonic EL speech. The perceptual accuracy of phrases was significantly higher than in monotonic EL speech when no categorical cue for listeners was provided, whereas they were at a close level when categorical information of the phrases was provided in advance. The acceptability of sentences was higher than that of monotonic EL speech. Conclusion: Using the tone-EL can produce Mandarin tones effectively and the quality of rehabilitated Mandarin is better than using a conventional-EL. To balance speech intelligibility and ease of use, a strategy -producing tonal speech when few informative cues are available to listeners is preferred.

The effect of age and gender of listeners on the perceptions of Mandarin electrolaryngeal speech was investigated. Sixty males and 40 females were categorized into five age groups (20–29, 30–39, 40–49, 50–59, and 60–70 years), who were regarded as naïve listeners for having no experience with electrolaryngeal speech. They were instructed to score acceptability of a passage and intelligibility of isolated words and embedded words. The results revealed no gender effects but significant age effects on the perceptual evaluation. It was more difficult for the 50–59 and 60–70 groups to understand electrolaryngeal speech. The results were also analyzed for tonal and segmental errors, and errors of tone alone were found to occur more often than segmental errors. In addition, a preliminary study was presented for the perceptions of the four Mandarin tones. Higher percent correct identification was found for the high-level tone compared to the other three tones.