The Proto-Greek language (also known as Proto-Hellenic) is an Indo-European language. It is assumed to be the last common ancestor of all known varieties of Greek, including Mycenaean Greek, the subsequent ancient Greek dialects (i. e., Attic, Ionic, Aeolic, Doric, Ancient Macedonian and Arcadocypriot) and, ultimately, Koine, Byzantine and Modern Greek together with its variants. The unity of Proto-Greek would have ended as Hellenic migrants, who spoke the predecessor of Mycenaean Greek, entered the Greek peninsula sometime in the Bronze Age.
Proto-Greek was originally a dialect of the Proto-Indo-European language. In the late Neolithic, speakers of this dialect, which would become Proto-Greek, migrated from their homeland (which could have been northeast of the Black Sea) to the Balkans and into the Greek peninsula. The evolution of Proto-Greek could be considered within the context of an early Paleo-Balkan sprachbund that makes it difficult to delineate exact boundaries between individual languages. The characteristically Greek representation of word-initial laryngeals by prothetic vowels is shared, for one, by the Armenian language, which also seems to share some other phonological and morphological peculiarities of Greek; this has led some linguists to propose a , although evidence remains scant.
Proto-Greek is mostly placed in the Early Helladic period (late 4th millennium BC; circa 3200 BC) towards the end of the Neolithic in Southern Europe. Ivo Hajnal dates the beginning of the differentiation of Proto-Greek into the Greek dialects to a point not significantly earlier than 1700 BC, however.
The primary sound changes separating Proto-Greek from the Proto-Indo-European language include:
Loss of prevocalic *s was not completed entirely, evidenced by sȳ́s ~ hȳ́s "pig" (from PIE *suh₁-), dasýs "dense" and dásos "dense growth, forest"; *som "with" is another example, contaminated with PIE *ḱom (Latin cum; preserved in Greek kaí, katá, koinós) to Mycenaean ku-su /ksun/, Homeric and Old Attic ksýn, later sýn. Furthermore, sélas "light in the sky, as in the aurora" and selḗnē/selā́nā "moon" may be more examples of the same if it derived from PIE *swel- "to burn" (possibly related to hḗlios "sun", Ionic hēélios < *sāwélios).
Dissimilation of aspirates (so-called Grassmann's law) caused an initial aspirated sound to lose its aspiration when a following aspirated consonant occurred in the same word. It was a relatively late change in Proto-Greek history and must have occurred independently of the similar dissimilation of aspirates (also known as Grassmann's law) in Indo-Iranian, although it may represent a common areal feature:
Greek is unique in reflecting the three different laryngeals with distinct vowels. Most Indo-European languages can be traced back to a dialectal variety of late Proto-Indo-European (PIE) in which all three laryngeals had merged (after colouring adjacent short /e/ vowels), but Greek clearly cannot. For that reason, Greek is extremely important in reconstructing PIE forms.
All of the cases may stem from an early insertion of /e/ next to a laryngeal not adjacent to a vowel in the Indo-European dialect ancestral to Greek (subsequently coloured to /e/, /a/, /o/ by the particular laryngeal in question) prior to the general merger of laryngeals:
A laryngeal adjacent to a vowel develops along the same lines as other Indo-European languages:
Proto-Greek underwent palatalization of consonants before *y. This occurred in two separate stages. The first stage affected only dental consonants, while the second stage affected all consonants.
The first palatalization turned dentals + *y into alveolar affricates:
Alongside these changes, the inherited clusters *ts, *ds and *tʰs all merged into *ts.
In the second palatalization, all consonants were affected. It took place following the resolution of syllabic laryngeals and sonorants. The following table, based on American linguist Andrew Sihler, shows the developments.
In post-Proto-Greek times, the resulting palatal consonants and clusters were resolved in varying ways. Most notably, *ň and *ř were resolved into plain sonorants plus a palatal on-glide, which eventually turned the preceding vowel into a diphthong.
In the time between the first and second palatalizations, new clusters *tsy and *dzy were formed by restoring a lost *y after the newly formed *ts and *dz. This occurred only in morphologically transparent formations, by analogy with similar formations where *y was preceded by other consonants. In formations that were morphologically opaque and not understood as such by speakers of the time, this restoration did not take place and *ts and *dz remained. Hence, depending on the type of formation, the Pre-Greek sequences *ty, *tʰy and *dy have different outcomes in the later languages. In particular, medial *ty becomes Attic s in opaque formations, but tt in transparent formations.
The outcome of PG medial *ts in Homeric Greek is s after a long vowel, and vacillation between s and ss after a short vowel: tátēsi dat. pl. "rug" < tátēt-, possí(n)/posí(n) dat. pl. "foot" < pod-. This was useful for the composer of the Iliad and Odyssey, since possí with double s scans as long-short, while posí with single s scans as short-short. Thus the writer could use each form in different positions in a line.
Examples of medial *ts (morphologically opaque forms, first palatalization only):
Examples of medial *ťť (morphologically transparent forms, first and second palatalization):
Sound changes between Proto-Greek and all early dialects, including Mycenaean Greek, include:
Note that /w/ and /j/, when following a vowel and not preceding a vowel, combined early on with the vowel to form a diphthong and so were not lost.
Loss of /h/ and /w/ after a consonant was often accompanied by compensatory lengthening of a preceding vowel.
The results of vowel contraction were complex from dialect to dialect. Such contractions occur in the inflection of a number of different noun and verb classes and are among the most difficult aspects of Ancient Greek grammar. They were particularly important in the large class of contracted verbs, denominative verbs formed from nouns and adjectives ending in a vowel. (In fact, the reflex of contracted verbs in Modern Greek, the set of verbs derived from Ancient Greek contracted verbs, represents one of the two main classes of verbs in that language.)
As Mycenaean Greek shows, the PIE dative (suffix -i), instrumental (suffix -phi) and locative (suffix -si) cases are still distinct and are not yet syncretized into other cases.
The pronouns hoûtos, ekeînos and autós are created. The use of ho, hā, to as articles is post-Mycenaean.
Proto-Greek inherited the augment, a prefix e-, to verbal forms expressing past tense. That feature is shared only with Indo-Iranian and Phrygian (and to some extent, Armenian), lending some support to a "Graeco-Aryan" or "Inner PIE" proto-dialect. However, the augment down to the time of Homer remained optional and was probably little more than a free sentence particle, meaning "previously" in the proto-language, which may easily have been lost by most other branches. Greek, Phrygian, and Indo-Iranian also concur in the absence of r-endings in the middle voice, in Greek apparently already lost in Proto-Greek.
The first person middle verbal desinences -mai, -mān replace -ai, -a. The third singular phérei is an innovation by analogy, replacing the expected Doric *phéreti, Ionic *phéresi (from PIE *bʰéreti).
The future tense is created, including a future passive as well as an aorist passive.