Curonian was an Indo-European language of the Baltic branch, as proven by Jānis Endzelīns.

[citation needed] Samogitian words such as kuisis (mosquito), pylė (duck), blezdinga (swallow), cyrulis (skylark), zuikis (hare), kūlis (stone), purvs (marsh), and pūrai (winter wheat) are considered to be of Curonian origin.

No written documents in this language are known, but some ancient Lithuanian texts from western regions show some Curonian influence.

[2]: 297 There are attested names of Curonian noblemen such as: Lammekinus [lv; lt], Veltūnas, Reiginas, Tvertikis, Saveidis.

[2]: 297 [10] Lord's Prayer after Simon Grunau Nossen thewes, cur tu es delbes sweytz gischer tho wes wardes penag munis tholbe mystlastilbi tolpes prahes girkade delbeszisne tade symmes semmes worsunii dodi mommys an nosse igdemas mayse unde gaytkas pames mumys nusze noszeginu cademes pametam musen prettane kans newede munis lawnā padomā swalbadi munis nowusse loyne Jhesus amen.