For believers, no communications media is more important than that connecting God with humans. Jews and Christians for more than 1500 years read the same sacred scripture, the Tanakh/the Old Testament, in the same language, Greek. Jews and Christians lived in close geographic proximity while interpreting the sacred text rather differently. They both engaged in bitter polemics. The more numerous and powerful Christians often viciously persecuted the Jews. Nonetheless, the Jews continued to use their sacred scripture in Greek translation. That use testifies to the great value of common communications media.
Jewish sacred scripture has been primarily transmitted in Hebrew. However, by the 3rd century BGC, most Jews spoke Aramaic, while the shared, spoken language of urban Hellenistic culture was Greek. Between the 3rd and 1st centuries BGC, Jews translated Jewish scripture into Greek to form the bible version known as the Septuagint. In the second century GC, the Jewish scholars Aquila, Symmachus, and Theodotion (the Three) translated Jewish scripture into Greek. Scripture in Hebrew remained the fundamental Jewish sacred text. However, translating Jewish scripture into Greek made Jewish scripture more accessible to Jews and non-Jews.
In the first century GC, a rapidly growing heretical Jewish/universalized sect called Christians recognized God’s words in Jewish scripture written in Greek. Christians interpreted Jewish scripture in light of the life of Jesus of Nazareth. The life stories of Jesus, the Gospels, quote Greek translations of Jewish scripture. Christians almost surely predominately discussed Jewish scripture in the more accessible Greek. As the Gospels amply indicate, Jesus created a bitter split within the Jewish community. Until recently, Jews were thought to have turned away from Greek translations of Jewish scripture as the increasing number of Christians actively used (mis-used) these translations.
New scholarship indicates that Jews and Christians shared Greek as a scriptural language for more than 1500 years. Texts from the Cairo Genizah indicate that Jews were carrying forward Greek translations of Aquila, Symmachus, and Theodotion about a millennium after they were made. Moreover, Greek glosses probably dating from the ninth century in an early Christian manuscript correspond to Greek texts found in the Cairo Genizah. Both in turn correspond to Greek text in a Jewish Greek translation, written in Hebrew letters, that was published in Constantinople in 1547. Hence Jews did not reject the Greek scriptural language that Christians embraced.
Christians responded directly to Jewish uses of Jewish sacred scripture. Under Louis IX, Christian church officials in France confiscated Jewish texts ostensibly to check them for errors. Many volumes of Jewish writings were burned in Paris in 1242. About the same time, in creating the Morgan Bible for Louis IX, Christian court officials seem to have struggled with what their criticisms of Jews meant for the production of that picture bible.
Sharing communications media tends to encourage conflict. But establishing and maintaining separate communications media is quite costly. Jews’ continuing use of the Greek Bible suggests that net benefits of common sacred communication in Greek outweighed those of insisting on sacred communication exclusively in Hebrew.
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 The Greek biblical translation called the Septuagint is also known as the LXX. Greek as used in this post refers to popularly spoken Greek. For the Hellenistic period, that Greek is called Koine Greek. The Greek of fifth-century Athens (classical or Attic Greek) differed significantly from Koine Greek.
 See de Lange (2007).
 The glosses are from the Codex Ambrosianus. See Boyd-Taylor (2007). The Greek Bible in Byzantine Judaism website makes a huge body of relevant evidence available to everyone around the world. It is a masterpiece of modern scholarship.
 The history of research section in the Greek Bible in Byzantine Judaism website discusses this shift in scholarly consensus. While the scholars whose research prompted the shift wrote this history, the Greek Bible in Byzantine Judaism website itself testifies to the universal force of the evidence.
 See Galbi (2003), Section III.C.
Boyd-Taylor, Cameron (2007). “The Greek Bible among Jews and Christians in the Middle Ages: The Evidence of Codex Ambrosianus,” in International Organization for Septuagint and Cognate Studies, and Melvin K. H. Peters. 2008. XIII Congress of the International Organization for Septuagint and Cognate Studies, Ljubljana, 2007. Atlanta, Ga: Society of Biblical Literature.
de Lange, Nicholas (2007). “Jewish Transmission of Greek Bible Versions,” in Peters (2008), XIII Congress, cited above.
Galbi, Douglas (2003). Sense in Communication.