The Collaborative International Dictionary of English v.0.48:

Madecass \Mad"e*cass\, Madecassee \Mad`e*cas"see\, prop. n.
   1. A native or inhabitant of Madagascar, or Madecassee. See
      Malagasy
      [1913 Webster]

   2. The language of the natives of Madagascar.
      [1913 Webster]