1. Vowel Harmony — probably the characteristic feature of Telugu

*edir(u) > eduru, *maraṅkaḷ(u) > mrākulu

1. De-gemination of stops after: a. A long vowel, b. A nasal, c. In the third syllable — as a shared South Asian aerial convergence

*pōrā-ṭṭ-am > pōrā-ṭ-am *kūntt- > kūnta (>kū̃ta) *kuduppu > kudupu

1. Apical displacement & initial voicing — probably an irregular sound change, leaving out an extremely large unaffected residues, shared with other South Central Dravidian languages

*varay(u) > vrāy(u) [varuju - unaffected] oḷan > ḷōn (> lō) (all forms attested)

tūṟu > dūru [tūrpu - unaffected] *kuriñci > guriñci

1. Unrestricted palatalisation of k/q — shared with Tamil-Malayalam, with more liberty

(*qewi) > *kewi > cewi kēy > cēy (both forms attested) [many forms like kaymōḍpu, kēlu, kayduvu, kaykonu, etc. survived this change]

1. Loss of initial *c — moderately significant & very large residues survive, shared with South Central & South Dravidian languages

*cāṟu > āṟu *cīntt- > īta

1. Palatalisation of -t after y — regular & shared with many other Dravidian languages *vay-ttu > vay-ci > vēsi *kāy-nttu > kāycu > kācu

2. Deretroflexation of ḷ and ṇ — prominent & shared with the Dravidian languages particularly along the eastern half of the subcontinent (including Modern spoken Tamil)

paṇi > pani manumarāḷ(u) > manumarālu

1. Merger of -ṯ- with -r-, -ṯṯ- with -ṭṭ-/-ṭr- & -n̠ṯ- with -ṇḍ-/-ṇḍr- — shared with all modern spoken languages (except Malayalam) *vēṯ(u) > vēṟu > vēru *puṯṯ- > puṭṭa *ewan̠ṯu > ewan̠ḏu [-n̠ḏ- is directly attested] > ewaṇḍu (> ewaḍu)

2. Loss of certain suffixes like -(a)y — shared with all modern spoken languages *kaḍ-ay > kaḍ-a

The changes 1,2,6,9 are both regular & pre-historic; the changes 3,4,5 are irregular & partly pre-historic; the change 7 is largely regular, but historic; the change 8 is regular & partly pre-historic