a. 三种语言的, 用三种语言的

[ adj ]
using or knowing three languages
<adj.all>
trilingual speakers

Trilingual \Tri*lin"gual\, a. [L. trilinguis; tri- (see {Tri-})
+ lingua tongue, language. See {Lingual}.]
Containing, or consisting of, three languages; expressed in
three languages.

The much-noted Rosetta stone . . . bears upon its
surface a trilingual inscription. --I. Taylor.