Jesus, being a Galilean Jew of the first century, most likely spoke Aramaic as his primary language.
This raises an intriguing question: How did he communicate with the Romans who occupied the region during that time?
In the Roman Empire, most people were bilingual or Trilingual. They could speak their "tribal" or historic/local language (yes, for Jesus that would be Aramaic), they could speak and often read Koine Greek (the language of books, schools, etc.) and Latin (the language of government and business). This is not as unusual as it seems to Americans.... in India, even quite poor people can speak their local tribal language, Hindi and English. In many European countries, people can speak, read and write in 2 or 3 languages.
When Jesus READS (yes, Jesus - from the very lowest level of society... likely a landless day laborer... could read) from the scroll in the Synagogue, He almost certainly is reading from the LXX, in GREEK. He could easily read Greek. But when He spoke to the congregation, He almost certainly spoke in Aramaic.
Israel was in the East where Greek was spoken far more than Latin, and so it's POSSIBLE that Jesus was not fluent in Latin. But the Roman leaders would know Greek - they'd need to in order to adequately communicate with the people they ruled. So, it's possible that when Jesus spoke with the Roman governor, that conversation may have been in Greek.... and language both of them would be fluent in.
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