Update

speech_synthesis.md

@@ -51,7 +51,7 @@ double speech(double t, double fundamental, double offset,
   /* now generate harmonics (multiples of fundamental frequency) as the source,
      and multiply them by the envelope given by formants (no need to deal with
      multiplication of spectra; as we're constructing the result from basic
-     frequencies, we can simply multiply each by one directly): */
+     frequencies, we can simply multiply each one directly): */
   while (1)
   {
     double f = harmonic * fundamental;