The Collaborative International Dictionary of English v.0.48:

Ladin \La*din"\, n. [From L. Latinus Latin. See Latin]
   1. A Romansch dialect spoken in some parts of Switzerland and
      the Tyrol.
      [1913 Webster]

   2. A person speaking Ladin as a mother tongue.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Ladin
    n 1: a Rhaeto-Romance dialect of Romansh spoken in southeastern
         Switzerland