Complex sentence: The northeastern Iberian script, also known as Levantine Iberian or Iberian, because is the Iberian script most frequently used, was the main mean of written expression of the Iberian language, language also expressed by the southeastern Iberian script and by the Greco-Iberian alphabet.
Split into simpler sentences: The northeastern Iberian script, is also known as Levantine Iberian or Iberian, because it is Iberian script most frequently used, and was the main mean of written expression of the Iberian language. The language is also expressed by the southeastern Iberian script and by the Greco-Iberian alphabet.