bilingual

from WordNet (r) 3.0 (2006)

bilingual
    adj 1: using or knowing two languages; "bilingual education"
    n 1: a person who speaks two languages fluently [syn:
         {bilingual}, {bilingualist}]

from The Collaborative International Dictionary of English v.0.48

Bilingual \Bi*lin"gual\, a. [L. bilinguis; bis twice + lingua
   tongue, language.]
   Containing, or consisting of, two languages; expressed in two
   languages; as, a bilingual inscription; a bilingual
   dictionary. -- {Bi*lin"gual*ly}, adv.
   [1913 Webster]