<<nationality and language>>
The people known as Greeks were Gentiles (non-Jews) of proper Greek ancestry or who spoke the Greek language fluently. The OT was written in Hebrew, and before the time of Christ was translated into Greek in a version known as the Septuagint. The NT was originally written in Greek. Many English words are derived from the Greek language.
The victorious Romans considered themselves properly educated if they could speak and write Greek, as this language was the universal medium of communication throughout much of the then known world around the time of Christ. Later it was superseded by Latin (Jn 19:24). Athens in Greece was a centre of advanced learning and philosophy (Act 17:18,21).
Belonging to the family of God transcends all barriers – “There is neither Jew nor Greek, slaves nor free, male nor female, for we are one in Christ Jesus (Gal 3:28).
See also: languages, translate/translation.