Of the language only a few glosses and brief comments in classical writers and scattered names on inscriptions survive. Altogether they add up to about 120 words, including place and personal names. Scattered vocabulary terms mentioned by Greek authors include άδάρκα (adarka), a type of plant, αδες (ades), "feet", βαρδοί (bardoi), "singing poets, bards", μάρκα (marka), "horse" and τριμαρκισία (
trimarkisia), "three-horse battle group".
The attested Galatian personal names are similar to those found elsewhere in the ancient Celtic-speaking world. Many are compound names containing common Celtic roots such as *brog-, "country, territory" (cf.
Old Irish mruig,
Breton bro; cognate with
Latin margo and
Gothic marka), *epo-, "horse" (Old Irish ech, Welsh eb- [in ebol "pony" and the compound ebrwydd "swift"]), *māro- (cf. Gaulish -māros, Old Irish mór, Welsh mawr, Breton meur) "great", and *rig(o)-, "king" (cf.
Gaulish -rīx/-reix, Irish rí, Welsh rhi; cognate with Gothic -reiks, Latin rēx). Examples include:
- Άδιατόριξ (Adiatorīx)
- Βιτοριξ (Bitorīx)
- Βρογιμάρος (Brogimāros)
- Κάμμα (Cāmmā)
- Δομνείων (Domneiū)
- Έπόνη (Eponī)
- Ολοριξ (Olorīx)
- Σμερτομάρα (Smertomārā)
- Τεκτομάρος (Tectomāros)
Tribal names include Ambitouti (Old Irish imm-, Welsh am "around"; Old Irish tuath, Welsh tut, "tribe"), Ριγόσαγες (Rigosages, "King-Seekers"; cf. Irish saigid "to go towards, to seek out", Welsh haedu, verbal suffix -ha "seeking"), and Τεκτόσαγες (Tectosages, cf. the related
Volcae Tectosages tribe of Gaul) "Travel-seekers" (Old Irish techt, "going, proceeding", Welsh taith, "journey, voyage").
Attested divine names include βουσσουριγίος (Bussurīgios) and Σουωλιβρογηνός (Suolibrogēnos), both identified with
Greek king of the gods
Zeus, and Ούινδιεινος (Uindieinos), perhaps the
tutelary god of the
Tolistobogiian town Ούινδια (Uindia).
Attested place names include Acitorīgiāco ("[Settlement of] Acitorīx"; compare Acitodunum in Gaul), Άρτικνιακόν (Articniācon, "[Settlement of] Artiknos" ["Bear-son"]), Δρυνέμετον (Drunemeton; <
Proto-Celtic *dru- "oak" or, simply, "great"; cf. Old Irish druí, Welsh dryw [< *dru-wid-s], "druid, wise man" [literally "greatly wise"], Old Irish neimed, Welsh nyfed "holy place, [sacred] grove"), the meeting place of the Galatian
tetrarchs and judges, and Ούινδια (Uindia; Old Irish finn, Welsh gwyn [masc.], gwen [fem.] "fair, white").
Survival into Early Medieval period
Sometime between 48–55,
Paul the Apostle wrote his
Epistle to the Galatians in
Greek, the medium of communication in the eastern parts of the
Roman Empire. This may mean that Galatians at the time were already bilingual in Greek, as St. Jerome later reports. However, scholars are divided as to whether Paul was writing to Greek Galatians or to the Hellenized descendants of the Celtic Galatians.
Lucian of Samosata recorded in circa AD 180 that the prophet
Alexander of Abonoteichus was able to find Celtic-speaking interpreters for his oracles in Paphlagonia (immediately northeast of Galatia).
Galen of Pergamon in the late 2nd century AD complained that the commonly spoken Greek of his day was being corrupted by borrowings of foreign words from languages such as Galatian.
In the 4th century
St. Jerome (Hieronymus) wrote in a comment to
Paul the Apostle's
Epistle to the Galatians that "apart from the Greek language, which is spoken throughout the entire East, the
Galatians have their own language, almost the same as the
Treveri". The capital of the Treveri was
Trier, where Jerome had settled briefly after studying in Rome.
In the 6th century AD,
Cyril of Scythopolis suggested
 that the language was still being spoken in his own day when he related a story that a monk from Galatia was temporarily possessed by
Satan and unable to speak; when he recovered from the "possession", he could respond to the questioning of others only in his native Galatian tongue.