hoarsen

from The Collaborative International Dictionary of English v.0.48

Hoarsen \Hoars"en\, v. t. [imp. & p. p. {Hoarsened}; p. pr. &
   vb. n. {Hoarsening}.]
   To make hoarse.
   [1913 Webster]

         I shall be obliged to hoarsen my voice.  --Richardson.
   [1913 Webster]