I am reading the Illustrated Encyclopedia of Ancient Greece by Nigel Rodgers.
On page 259, it says that Jesus and Pontius may have spoken Greek, plus ‘Without the impact of Hellenism, Christianity might have just been an obscure heretical Jewish sect...’
1.) Is there any evidence of the Palestine colony speaking Greek as the primary language in Ancient Israel, under the reign of Rome?
2.) Does the claim that ‘without Hellenism roots, Christianity may have not existed as it does today,’ have any merit?
:Edit:
Fixing some grammar
Pontius Pilate almost certainly spoke Greek. Greek was the prestige language spoken by Roman and non-Roman elites in the Eastern Mediterranean from roughly 300 BC to roughly 650 AD (and later depending on where). A unilingual Latin speaker would not have had many people they could speak to in and around Judaea.
There are massive amounts of evidence that since Alexander the Great conquered the Middle East, there were significant Greek speaking populations throughout the area, particularly anywhere in proximity to the Mediterranean, and that it was the lingua franca of the elite. Roman elites also tended to be bilingual in Latin and Greek. While not all Roman elites were bilingual, the idea of sending a unilingual Latin speaker to govern a region like this is about as absurd as the idea of Belgium sending a unilingual francophone to be ambassador to the Netherlands.
It's unlikely that Greek was the "primary" language in the sense of being the majority, but it would have been the common language between Romans and locals.
Whether or not Jesus would have spoken Greek is harder to know for sure. We know less about the lives of people of more modest backgrounds, but I wouldn't rule it out.
The second claim IMO is pretty well founded. The reason that Christianity did not remain a Jewish sect is, tautologically, because non Jews adopted Christianity. Saint Paul played a big part in this, and the gentiles that he evangelized were largely Hellenic. Look are the names of the Pauline Epistles, you don't need to be an expert on the ancient world to guess that the Corinthians, Philippians, Thessalonians, and Ephesians were Greek speakers. There was also a great deal of religious uncertainty among Hellenistic gentiles at this time. There was a significant population of Jewish curious Hellenic "god-fearers" who didn't want to take the final difficult step of becoming Jewish. These folks were an ideal audience for Christianity. Early Christianity made its strongest inroads in the Greek community in the early years, with significant Christian populations in many Greek areas long before Christianity was a significant factor in the West.