Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
Latvian [ˈlætvɪən] adj латви́йский
n латы́ш(ка) (LING) латы́шский язы́к#
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
Русский: