Clay tablets with Mycenaean Greek in Linear B have been found over a wide area, from Thebes in Central Greece, to Mycenae and Pylos on the Peloponnese, to Knossos on Crete.
It was originally spoken in eastern Greece north of the Peloponnese: in Thessaly, in Locris, Phocis, and southern Aetolia, and in Boeotia, a region close to Athens.
Boeotian underwent vowel shifts similar to those that occurred later in Koine Greek, converting /ai̯/ to [ɛː], /eː/ to [iː],[7] and /oi̯/ to [yː].
This long vowel then merged with /ɛː/ and was noted ⟨Η⟩ in the Ionic alphabet (which became used by the Athenians in the classical era)[7][13] All other East and West Greek dialects retain original /aː/.
It underwent many sound changes, including development of aspirated and voiced stops into fricatives and the shifting of many vowels and diphthongs to [i] (iotacism).
The letter rho ρ was pronounced as an alveolar trill [r], as in Italian or Modern Greek rather than as in standard varieties of English or French.
In some cases, initial ⟨ρ⟩ in poetry was pronounced as a geminate (phonemically /rr/, phonetically [r̥ː]), shown by the fact that the previous syllable is counted as heavy: for instance τίνι ῥυθμῷ must be pronounced as τίνι ρρυθμῷ in Euripides, Electra 772, τὰ ῥήματα as τὰ ρρήματα in Aristophanes’ play The Frogs 1059, and βέλεα ῥέον as βέλεα ρρέον in Iliad 12.159.
[22] In the table below the scansion of the examples is shown with the breve ⟨˘⟩ for light syllables, the macron ⟨¯⟩ for heavy ones, and the pipe ⟨|⟩ for the divisions between metrical feet.
Single and double (geminated) consonants were distinguished from each other in Ancient Greek: for instance, /p kʰ s r/ contrasted with /pː kʰː sː rː/ (also written /pp kkʰ ss rr/).
The close front rounded vowels /y/ and /yː/ (an evolution of /u/ and /uː/ respectively) are both represented in writing by the letter upsilon (υ) irrespective of length.
In Classical Attic, the spellings ει and ου represented respectively the vowels /eː/ and /uː/ (the latter being an evolution of /oː/), from original diphthongs, compensatory lengthening, or contraction.
The above information about the usage of the vowel letters applies to the classical orthography of Attic, after Athens took over the orthographic conventions of the Ionic alphabet in 403 BC.
In the earlier, traditional Attic orthography there was only a smaller repertoire of vowel symbols: α, ε, ι, ο, and υ.
Later grammarians, during the time of the Hellenistic Koine, developed that symbol further into a diacritic, the rough breathing (δασὺ πνεῦμα; Latin: spiritus asper; δασεῖα for short), which was written on the top of the initial vowel.
Correspondingly, they introduced the mirror image diacritic called smooth breathing (ψιλὸν πνεῦμα; Latin: spiritus lenis; ψιλή for short), which indicated the absence of /h/.
[19] Ancient grammarians, such as Aristotle in his Poetics and Dionysius Thrax in his Art of Grammar, categorized letters (γράμματα) according to what speech sounds (στοιχεῖα 'elements') they represented.
[16] The glottal fricative /h/ was originally called πνεῦμα ('breath'), and it was classified as a προσῳδία, the category to which the acute, grave, and circumflex accents also belong.
The following section provides a short summary of the kinds of evidence and arguments that have been used in this debate, and gives some hints as to the sources of uncertainty that still prevails with respect to some details.
However, both types of evidence are often difficult to interpret, because the phonetic terminology of the time was often vague, and it is often not clear in what relation the described forms of the language stand to those which were actually spoken by different groups of the population.
That led him, for instance, to posit that the various letters which in the iotacist system all denoted [i] must have had different values, and that ει, αι, οι, ευ, αυ, ου were all diphthongs with a closing offglide.
He also insisted on taking the accounts of ancient grammarians literally, for instance where they described vowels as being distinctively long and short, or the acute and circumflex accents as being clearly distinguished by pitch contours.
He also fell victim to a few spurious relations due to mere accidental similarity (e.g. Greek θύειν 'to sacrifice' — French tuer, 'to kill').
In other areas, his arguments are of quite the same kind as those used by modern linguistics, e.g. where he argues on the basis of cross-dialectal correspondences within Greek that η must have been a rather open e-sound, close to [a].
At the same time, continued work in philology and archeology was bringing to light a growing corpus of non-standard, non-literary and non-classical Greek writings, e.g. inscriptions and later also papyri.
For the consonants, historical linguistics established the originally plosive nature of both the aspirates ⟨φ,θ,χ⟩ [pʰ, tʰ, kʰ] and the mediae ⟨β, δ, γ⟩ [b, d, ɡ], which were recognised to be a direct continuation of similar sounds in Indo-European (reconstructed *bʰ, *dʰ, *gʰ and *b, *d, *g).
Work was also done reconstructing the linguistic background to the rules of ancient Greek versification, especially in Homer, which shed light on syllable structure and accent.
Scholars also described and explained the regularities in the development of consonants and vowels under processes of assimilation, reduplication, compensatory lengthening etc.
Comparative linguistics could in this way establish that a certain phonology, roughly along the Erasmian model, had once existed, and that significant changes had to have occurred later, during the development towards Modern Greek.
Since the 1970s and 1980s, several scholars have attempted a systematic re-evaluation of the inscriptional and papyrological evidence (Smith 1972, Teodorsson 1974, 1977, 1978; Gignac 1976; Threatte 1980, summary in Horrocks 1999).
Τῆς δὲ λέξεως ἁπάσης τάδ᾽ ἐστὶ τὰ μέρη, στοιχεῖον συλλαβὴ σύνδεσμος ὄνομα ῥῆμα ἄρθρον πτῶσις λόγος.