anlaut

from The Collaborative International Dictionary of English v.0.48

Anlaut \An"laut`\, n. [G.; an on + laut sound.] (Phon.)
   An initial sound, as of a word or syllable.
   [1913 Webster]

   {Im anlaut}, initially; when initial; -- used of sounds.
      [Webster 1913 Suppl.] Ann