Voicing of Stop Consonants
Does voicing of stop consonants /b/, /p/, /d/, /t/, /g/, and /k/ affect intelligibility in English as a Lingua Franca?
ELF speakers in this study produced stop consonants with a wide range of voicing (as measured by Voice Onset Time), but listeners were able to correctly identify /d/, /t/, /g/, and /k/ most of the time regardless of VOT. For /b/ and /p/ listeners often heard the opposite of what speakers intended. Perception and pronunciation instruction in ELF contexts can focus on /b/ and /p/ specifically.
Listeners did better understanding clusters in initial position than in final position. Overall and for final position, listeners were able to understand clusters correctly more than acoustic results would suggest. However, deletion of one of the sounds of a cluster often led to mismatch. Other strategies of cluster resolution (such as vowel epenthesis) were not so damaging to understanding. Pronunciation instruction can focus on clusters in initial position and helping ELF users avoid deletion.
Does vowel length affect intelligibility in English as a Lingua Franca?
Certain vowels in English are either always long or always short when pronounced by native speakers. ELF listeners were affected by pronounced vowel length partially when listening to ELF. Short vowels were often misunderstood for other short vowels and long vowels were often misunderstood for other long vowels. Pronunciation teachers can focus on helping ELF users produce vowels with the right length, even if the vowel quality isn’t quite right.