Benedick means Claudio's speaking is unnecessarily elaborate.
When Benedick refers to Claudio's new way of speaking as a "fantastical banquet," he means that it is unnecessarily elaborate. Claudio's words are like a feast with overly complicated and excessive dishes, indicating that his speech is now overly ornate and showy compared to his previous plain and direct way of speaking.
https://brainly.com/question/1888939