As with the Illyrian and Ligurian languages, the surviving corpus of Gallaecian is composed of isolated words and short sentences contained in local Latin inscriptions or glossed by classical authors, together with a number of names – anthroponyms, ethnonyms, theonyms, toponyms – contained in inscriptions, or surviving as the names of places, rivers or mountains. In addition, many isolated words of Celtic origin preserved in the present-day Romance languages of Portugal and Northwest Spain, are likely to have been inherited from ancient Gallaecian. Classical authors such as Pomponius Mela and Pliny the Elder wrote about the existence of Celtic and non-Celtic populations in Gallaecia and Lusitania, but several modern scholars have postulated Lusitanian and Gallaecian as a single archaic Celtic language. Others point to major unresolved problems for this hypothesis, such as the mutually incompatible phonetic features, most notably the proposed preservation of *p in Lusitanian and the inconsistent outcome of the vocalic liquid consonants, so addressing Lusitanian as a non-Celtic language and unrelated to Gallaecian, although cultural influences were likely.
Characteristics
Some of the main characteristic of Gallaecian shared with Celtiberian and the other Celtic languages were :
Indo-European *-ps- and *-ks- became *-xs- and were then reduced to -s-: place name AVILIOBRIS from *Awil-yo-brix-s < Proto-Celtic *Awil-yo-brig-s 'Windy hill', modern place name Osmo from *Uχsamo- 'the highest one'.
Original PIE *p has disappeared, having become a *φ sound before being lost completely: place names C OLCA from *φolkā- 'Overturned', C ERITAECO from *φerito- 'surrounded, enclosed', personal name ARCELTIUS, from *φari-kelt-y-os; place name C ERCORIOBRI, from *φeri-kor-y-o-brig-s 'Overshooting hillfort'; place name C LETIOBRI, from *φle-tyo-brig-s 'wide hillfort', or *φlei-to-brig-s 'grey hillfort'; place name Iria Flavia, from *φīweryā- 'fertile' ; place name ONTONIA, from *φont-on- 'path'; personal name LATRONIUS, to *φlā-tro- 'place; trousers'; personal name ROTAMUS, to *φro-tamo- 'foremost'; modern place names Bama to *uφamā- 'the lowest one, the bottom', Iñobre to *φenyo-brix-s 'Hill by the water', Bendrade to *Vindo-φrātem 'White fortress', and Baiordo to *Bagyo-φritu-, where the second element is proto-Celtic for 'ford'. Galician-Portuguese appellative words leira 'flat patch of land' from *φlāryā, lavego 'plough' from *φlāw-aiko-, laxe/lage 'flagstone', from medieval lagena, from *φlagĭnā, rega and rego 'furrow' from *φrikā.
Indo-European sonorants between vowels, *n̥, and *m̥ have become an, am; *r̥, and *l̥ have become ri, li: place name Brigantia from *brig-ant-yā < Proto-Celtic *br̥g-n̥t-y-ā < post-Proto-Indo-European *bʰr̥gʰ-n̥t-y-ā 'The towering one, the high one'; modern place names in Portugal and Galicia Braga, Bragança, Berganzo, Berganciños, Bergaña; ancient place names AOBRIGA, CALIABRIGA, CALAMBRIGA, CONIMBRIGA, CORUMBRIGA, MIROBRIGA, NEMETOBRIGA, COELIOBRIGA, TALABRIGA with second element *brigā < Proto-Celtic *br̥g-ā < post-PIE *bʰr̥gʰ-ā 'high place', and AVILIOBRIS, MIOBRI, AGUBRI with second element *bris < *brix-s < Proto-Celtic *brig-s < *br̥g-s < PIE *bʰr̥gʰ-s 'hill'; cf. English cognate borough < Old English burg "fort" < Proto-Germanic *burg-s < PIE *bʰr̥gʰ-s.
Reduction of diphthong *ei to ē: theonym DEVORI, from *dēwo-rīg-ē < Proto-Celtic *deiwo-rēg-ei 'To the king of the gods'.
Lenition of *m in the group *-mnV- to -unV-: ARIOUNIS MINCOSEGAECIS, dative form from *ar-yo-uno- *menekko-seg-āk-yo- 'To the fields of the many crops' < Proto-Celtic *ar-yo-mno-....
Assimilation *p.. kʷ > *kʷ.. kʷ: tribe name Querquerni from *kʷerkʷ- < PIE *perkʷ- 'oak, tree'. Although this name has also been interpreted as Lusitanian by B. M. Prósper, she proposed recently for that language a *p.. kʷ > *kʷ.. kʷ > *p.. p assimilation.
Reduction of diphthong *ew to *ow, and eventually to ō: personal names TOUTONUS / TOTONUS 'of the people' from *tout- 'nation, tribe' < PIE *teut-; personal names CLOUTIUS 'famous', but VESUCLOTI 'having good fame' < Proto-Celtic *Kleut-y-os, *Wesu-kleut-os; CASTELLO LOUCIOCELO < PIE *leuk- 'bright'. In Celtiberian the forms toutinikum/totinikum show the same process.
Superlatives in -isamo: place names BERISAMO < *Berg-isamo- 'The highest one', SESMACA < *Seg-isamā-kā 'The strongest one, the most victorious one'. The same etymology has been proposed for the modern place names Sésamo and Sísamo, from *Segisamo-; modern place name Méixamo from Magisamo- 'the largest one'.
Syncope of unstressed vowels in the vicinity of liquid consonants: CASTELLO DURBEDE, if from *dūro-bedo-.
Reduction of Proto-Celtic *χt cluster to Hispano-Celtic *t: personal names AMBATUS, from Celtic *ambi-aχtos, PENTIUS < *kwenχto- 'fifth'.
Some characteristics of this language not shared by Celtiberian:
In contact with *e or *i, intervocalic consonant *-g- tends to disappear: theonym DEVORI from *dēworīgē 'To the king of the gods'; adjective derived of a place name SESMACAE < *Seg-isamā-kā 'The strongest one, the most victorious one'; personal names MEIDUENUS < *Medu-genos 'Born of mead', CATUENUS < *Katu-genos 'Born of the fight'; inscription NIMIDI FIDUENEARUM HIC < *widu-gen-yā. But Celtiberian place name SEGISAMA and personal name mezukenos show preservation of /g/.
*-lw- and *-rw- become -lβ-, -rβ- : MARTI TARBUCELI < *tarwo-okel- 'To Mars of the Hill of the Bull', but Celtiberian TARVODURESCA.
Late preservation of *φl- which becomes βl- and only later is reduced to a simple l- sound: place names BLETISAM, BLETIS, modern Ledesma < *φlet-isamā 'widest'; BLANIOBRENSI, medieval Laniobre < *φlān-yo-brigs 'hillfort on the plain'. But Celtiberian place name Letaisama.
*wl- is maintained: VLANA < PIE *wl̥Hn-eh₂ 'wool', while Celtiberian has l-: launi < PIE *wl̥H-mn-ih₂ 'woolly'.
Sometimes *wo- appears as wa-: VACORIA < *wo-kor-yo- 'who has two armies', VAGABROBENDAM < *uφo-gabro-bendā 'lower goat mountain'.
Dative plural ending -bo < PIE *bʰo, while Celtiberian had -bos: LUGOUBU/LUCUBO 'To Lug'.
Gallaecian appears to be a Q-Celtic language, as evidenced by the following occurrences in local inscriptions: ARQVI, ARCVIVS, ARQVIENOBO, ARQVIENI, ARQVIVS, all probably from IE Paleo-Hispanic *arkʷios 'archer, bowman', retaining proto-Celtic *kʷ. It is also noteworthy the ethnonyms Equaesi, a people from southern Gallaecia, and the Querquerni. Nevertheless, some old toponyms and ethnonyms, and some modern toponyms, have been interpreted as showing kw / kʷ > p: Pantiñobre valley' and *brix-s 'hill and Pezobre, ethnonym COPORI "the Bakers" from *pokwero- 'to cook', old place names Pintia, in Galicia and among the Vaccei, from PIE *penkwtó- > Celtic *kwenχto- 'fifth'.
