The Curonian language (German: Kurisch; Latvian: kuršu valoda; Lithuanian: kuršių kalba), or Old Curonian, was a nearly unattested Baltic language spoken by the Curonians, a Baltic tribe who inhabited the Courland Peninsula (now western Latvia) and the nearby Baltic shore.
Curonian left substrata in western dialects of the Latvian and Lithuanian, namely the Samogitian dialect. No written documents in this language are known, but some ancient Lithuanian texts from western regions show some Curonian influence. According to Lithuanian linguist Zigmas Zinkevičius, long and intense Curonian–Lithuanian bilingualism existed.
