from The American Heritage® Dictionary of the English Language, 5th Edition.
- transitive verb To devoice.
from The Century Dictionary.
- In phonetics, to deprive of voice, or sonant quality; render non-sonant or surd.
Sorry, no etymologies found.
Individuals perhaps tended to anticipate a little the voiceless release and to unvoice the latter part of the final l-sound (very much as the l of English words like felt tends to be partly voiceless in anticipation of the voicelessness of the t).