The Andhra (Saatavaahana) dynasty introduced the braahmee to the present day Kannada and Telugu regions. The earliest inscriptions found in the Tamil land belong to more or less the same period. A number of early Satavahana coins and other remains were found in Tamil Nadu. It is therefore reasonable to assume that Satavahanas introduced the script to the Tamil country also. The Satavahanas were, for some time, vassals of the Mauryan Empire. Mauryan Emperor Asoka the great (reign: 269-232 BCE) and the rise of Buddhism played stellar roles in championing this spread of writing. Thus, Telugu and all the other south Indian languages had developed from the proto-dravidian language of the Indus valley while their scripts descended from the braahmee.
The evolution of Telugu can be traced through centuries in terms of its form as well as its function. Although culturally Telugu is close to its southern neighbours -- Tamil and Kannada -- genetically, it is closer to its northern neighbours -- Gondi, Konda, Kui, Kuvi, Pengo and Manda. There is evidence to show that these languages were freely borrowed from Telugu even from the prehistoric period whereas borrowing between Telugu and Tamil and Kannada has been mostly during the historic period, i.e., post-5th century B.C.
Its vocabulary is very much influenced by Sanskrit. In the course of time, some Sanskrit expressions used in Telugu got so naturalised that people regarded them as pure Telugu words. Some Kannada and Tamil words were also taken into Telugu but they did not gain much currency.
With the advent of the Muslim rule, several Persian and Arabic words entered into the Telugu language. But they were confined to the spoken language and to the language of the judiciary and the executive. The influence of Persian and Arabic is discernible to a considerable extent in the languages spoken in Telangana due to its long association with the Muslim rule. There is also a great element of English words in the vocabulary of Coastal Andhra and Rayalaseema because these regions were directly under the British rule for nearly a century and a half.
It is possible to identify broadly four stages in the history of the Telugu language.
(1) B.C. 200 -- A.D. 500
During the this period, we only come across names of places and personal names of Telugu in Prakrit and Sanskrit inscriptions found in the Telugu country. Telugu was exposed to the influence of Prakrit as early as the 3rd century B.C. From this we know that the language of the people was Telugu, although the language of the rulers was different. The first complete Telugu inscription belongs to the Renati Cholas, found in Erragudipadu, Kamalapuram taluk of Cuddapah district and assigned to about A.D. 575. Telugu was exposed to the influence of Sanskrit about this period. It appears that literature also existed in Telugu about the same time, because we find literary style in the inscriptions some three centuries even before Nannaya's (A.D. 1022) Mahabharatam. During the time of Nannaya, the popular language had considerably diverged from the literary language.
In the period A.D. 500--1100, the literary languages confined to the poetic works, flourished in the courts of kings and among scholars. Phonetic changes, which occurred in the popular language, are reflected in the literary language, although the two streams remained apart in grammar and vocabulary.
During A.D. 1100--1400 the literary language got stylized and rigid, closing itself from the influence of contemporary spoken language. Ketana (13th century AD), a disciple of Tikkana prohibited the use of spoken words in the poetic works and quoted some spoken forms.
During the period A.D. 1400--1900, many changes culminating in today's form of Telugu took place.
The prose language of the 19th century, as can be seen from the `Kaifiyats', shows the educated speech as base with occasional influence of literary language. We also notice the influence of Urdu language on Telugu before the spread of English education.
From the foregoing overview of the history of the Telugu language, one can see that what we now use as modern standard Telugu, had its beginnings in the spoken variety, right from the 10th century A.D. The language was progressively enriched by contact with Sanskrit, Prakrit, Urdu and English from early times.