Much of it is found in the gospels Matthew, Mark, and Luke. However, in the Old Testament there are examples of speech we know have not been stylized. The prime example is found in 2 nd Kings 18.27. In this passage the commander of the Assyrian army has surrounded Jerusalem and is taunting the Judean leaders. Even in English it sounds like a rather vulgar taunt, but in Hebrew it is even more so.
Scripture is primarily a record of written communication.
There are lots of laws, many stories, and much poetry. When we read a passage we should be aware of the type of literature we're reading if we want it to make sense.