Proto-Dravidian is the proto-language of the Dravidian languages.

Hypothetical language

Proto-languages are, by definition, hypothetical languages reconstructed by linguists, and hence no proto-language has any historical record. So is the case with Proto-Dravidian. Due to a dearth of comparative linguistic research into the Dravidian languages, not many details as to the grammar, epoch, or location of Proto-Dravidian are known.

Differentiation

It is thought to have differentiated into Proto-North Dravidian, Proto-Central Dravidian and Proto-South Dravidian around 500 BC, although some linguists have argued that the degree of differentiation between the sub-families points to an earlier split. The only book which covers all the Dravidian languages which can point to Proto-Dravidian forms is Dravidian Etymological Dictionary still consist only of lists of related words without further explanation; therefore for a talented linguist Proto-Dravidian offers large possibilities.

The Reconstructed Language

Here we discuss the salient features of the reconstructed Proto-Dravidian language.

Historical Phonology

Vowels: Proto-Dravidian contrasted between five short and long vowels: *a, *ā, *i, *ī, *u, *ū, *e, *ē, *o, *ō. The sequences *ai and *au are treated as *ay and *av (or *aw)
Consonants: Proto-Dravidian is reconstructible with the following consonantal phonemes (Subrahmanyam 1983:p40, Zvelebil 1990, Krishnamurthi 2003):

The alveolar stop in many daughter languages developed into an alveolar trill . The stop sound is retained in Kota and Toda (Subrahmanyam 1983). Malayalam still retains the original (alveolar) stop sound in gemination. (ibid). In Old Tamil it took the enunciative vowel like the other stops. In other words, (or ) did not occur word-finally without the enunciative vowel (ibid).

Velar nasal occurred only before in Proto-Dravidian (as in many of its daughter languages). Therefore it is not considered a separate phoneme in Proto-Dravidian. However, it attained phonemic status in languages like Malayalam, Gondi, Konda and Pengo due to the simplification of the original sequence * to . (Subrahmanyam 1983)

The glottal fricative has been proposed by Bh. Krishnamurthi to account for the Old Tamil Aytam (Āytam) and other Dravidian comparative phonological phenomena (Krishnamurthi 2003).

Homeland

The Dravidian languages have been found mainly in South India since the start of the common era. Speculations regarding the original homeland being a mythical sunken continent called Kumari Kandam, or the Indus Valley Civilization are largely discredited in academic circles.
Iravatham Mahadevan, who with his knowledge of both Tamil and Sanskrit, spent many decades studying the IVC script said in an interview in 1998 that IVC script is undeciphered. According to Michael Witzel, the well-known Indologist, there are not many Dravidian loan words in the earliest stratum of Vedas, even though, the Dravidian influence quickly increases in the post-Rigvedic period. In the essay "Substrate Languages in Old Indo-Aryan", Prof. Witzel says "As we can no longer reckon with Dravidian influence on the early RV, this means that the language of the pre-Rigvedic Indus civilization, at least in the Panjab, was of (Para-) Austro-Asiatic nature."

Spread

Many linguists tend to favour the theory that speakers of Dravidian languages spread southwards and eastwards through the Indian subcontinent, based on the fact that the southern Dravidian languages show some signs of contact with linguistic groups which the northern Dravidian languages do not.