Proto-Basque language

Proto-Basque (aitzineuskara; protoeuskera, protovasco; proto-basque) is a reconstructed ancient stage of the Basque language. It preceded another reconstructed stage, Common Basque, which is derived by comparing dialects of modern Basque. Common Basque is their reconstructed common ancestor. Proto-Basque is based on the comparison also of words that precede Common Basque, such as Latin words in Basque, and toponyms. Common Basque is dated to the 5th and 6th centuries, while Proto-Basque stage can be roughly dated to the last centuries BCE, before the Roman conquests in the Western Pyrenees.

The foundation for the study of both stages was laid out by the Basque linguist Koldo Mitxelena. The topic was launched by him in the first edition of Fonética histórica vasca in 1961.

Background
The first linguist who scientifically approached the question of the historical changes that Basque had undergone over the centuries was Koldo Mitxelena. His work on Proto-Basque focused mainly on between the 5th century BCE and the 1st century CE, just before and after initial contact with the Romans. By comparing variants of the same word in modern dialects and the changes that Latin loanwords had undergone, he deduced the ancestral forms and the rules for historical sound changes. His groundbreaking work, which culminated with the publication of his book Fonética histórica vasca (1961) (a revised version of his doctoral thesis of 1959), was carried out mostly before the Aquitanian inscriptions were found, but they fully backed up Mitxelena's proposed Proto-Basque forms.

Since then, a number of other prominent linguists, such as Larry Trask, Alfonso Irigoien, Henri Gavel and most recently Joseba Lakarra, Joaquín Gorrotxategi and Ricardo Gómez, have made further contributions to the field. Some of them, such as Lakarra, have focused their attention on even older layers of the language, called Pre-Proto-Basque (or Old Proto-Basque), that preceded the Celtic invasion of Iberia.

Direct attestations of Proto-Basque
Onomastic attestations of the Aquitanian language, which is only known from the names of places, persons and deities in inscriptions from the first centuries CE, closely match the reconstructed form of Proto-Basque. For instance, Aquitanian names contain elements such as Seni- or Sembe- that fully correspond to the reconstructed Proto-Basque words *seni 'boy' and *sembe 'son'.

A small sample of what is thought to be a form of Proto-Basque has been discovered on the Hand of Irulegi, an inscribed bronze artifact in the shape of a right hand dated to the 1st century BC.

Phonology
The consonant system of Proto-Basque was reconstructed by Mitxelena as follows:

The characteristic fortis–lenis contrast was realized in three ways:
 * Duration: fortis consonants were pronounced longer than their lenis counterparts; for sonorants, this was the main contrast, rhotics were additionally distinguished as trill $⟨p, t, k⟩$ vs. tap $⟨b, d, g⟩$ as in Modern Basque
 * Occlusion: fortis stops and sibilants were fully occlusive, their lenis counterparts only partially so; fortis sibilants thus were affricates, lenis sibilants were fricatives
 * Voicing: lenis stops were generally voiced, while fortis stops were always unvoiced.

This consonant system differed in many ways from the consonant system in Modern Basque dialects: most notable is the lack of /m/, /p/, the semivowels /w/ and /y/, and the entire palatal consonant series in Proto-Basque, and on the other hand the distinction between fortis and lenis nasals and laterals which is not found in the modern language.

This relatively small consonant system was further subject to positional restrictions: only the lenes $⟨R⟩$ occurred at the beginning of a word (also $⟨r⟩$, but only in auxilliary verbs), while only fortes were allowed in final position. The fortis–lenis contrast was therefore restricted to word-internal position.

Evidence for the Proto-Basque consonant system comes from sound correspondences between modern dialects, the distribution of sounds in native (i.e. non-borrowed) vocabulary, and from the phonological adaptation of early Latin/Romance borrowings. E.g., the positional restrictions of Proto-Basque explain why the Common Romance affricate in /tselu/ 'sky' (< Classical Latin caelum) became a fricative in Basque (zeru) at the beginning of a word, whereas the simple fricative at the end of the Latin word corpus 'body' was adopted as an affricate in Basque (gorputz). Further, the voicing contrast of stops in Latin/Romance borrowings was only preserved in medial position (e.g. lacum > laku 'lake' versus regem > errege 'king'), but not in word-initial position due to the lack of the fortis-lenis contrast in this position; thus for instance, both p- and b- became b- in Basque: benedica- > beindika 'bless', pacem > bake 'peace'.

Studying the behaviour of Latin and early Romance loanwords in Basque, Mitxelena discovered that Proto-Basque *n was lost between vowels and that Proto-Basque had no *m. Both are relatively unusual cross-linguistically, but /n/ was also partially deleted between vowels during the history of the nearby Gascon and Galician-Portuguese.

Old Proto-Basque
One of the puzzles of Basque is the large number of words that begin with vowels in which the initial and second vowels are the same. Joseba Lakarra proposes that in Pre-Proto-Basque there was extensive reduplication and that later, certain initial consonants were deleted, leaving the VCV pattern of Proto-Basque: