Final answer:
Casca's line "It was Greek to me" is likely a statement of confusion or lack of understanding, drawing on the historical context of the complexity of the Greek language to those not versed in it.
Step-by-step explanation:
Casca's line "It was Greek to me" (line 377) is most likely meant to convey that the speaker did not understand something. This phrase originates from the fact that Greek language was seen as complex and unintelligible to those not knowledgeable in it, much like complex subjects may seem to those not familiar with them. Considering the historical context, during which the Roman elite may have known Greek, those like Casca, who did not comprehend it, found themselves perplexed or alienated by the language barrier. Thus, when Casca says "It was Greek to me," he is indicating that he could not grasp or decipher the meaning of what was said, much as an English speaker today might use the expression to indicate that they did not understand something because it was too complex or foreign in nature.