Before the arrival of the Romans in Iberia a number of languages were spoken, and some writing systems had evolved, frequently borrowing from Greek and Phoenicians, who had established trading colonies on the peninsula. Aquitanian, or Proto-Basque, was an ancestor of modern Basque, and was spoken in the in the Pyrenean region Iberian bears a close relationship to the Vasconic languages, while Tartessian appears to be outside the Indo-European language family, although it borrowed many Celtic place name. Celto-Iberian is an extinct Indo-European language of the Celtic branch. The Iberian language, spoken in the east of the peninsula, was written in Iberian script, a system of 28 syllabic and alphabetic characters, which may well have derived from contact with Greek and Phoenician trading colonies. This writing system was retained until the Roman conquest. The Turdetanians were an ancient people living in the Guadalquivir valley. Their language was closely related to the Tartessians. The Tartessian language, which has been traced through some 95 extant inscriptions, was mainly located in the south and southeast of the peninsula. Many of the characters of the script closely relate to Phoenician letterforms.