The Andhras was mentioned in Aitareya Brahmana, which is as follows:
This Risi Visvamitra had a hundred sons, fifty of them were older
than Madhuchhandtls, and fifty were younger than he. The older ones
were not pleased with (the installation of SunaWepa to the primogeni-
VisvAmitra then pronounced against them the curse,
" You shall have the lowest castes for your descendants."
Therefore are many of the most degraded classes of men, the rabble for
the most part, such as the Andhras, Pwidras, Saharas, Paltndas, and
Miitibas, descendants of Visvamitra.
But Madhuchhandas, with the fifty younger sons, said, " What our
father approves of, by that we abide ; we all accord to thee
(^unahsepa) the first rank, and we will come after thee ! "
Vijivtlmitra, (leligated 'at this answer) then praised these sons
with the following verses :
" Ye my sons will have abundance of cattle and children, for you have
made me rich in children by consenting to my wish."
The same Andhras might have lived in trIlinga desa, as stated in the question, and later the language got the name Telugu.