The spelling of the word "most prating" can be broken down using IPA phonetic transcription. "Most" is pronounced /moʊst/ with a long "o" sound and a "st" ending. "Prating" is pronounced /ˈpreɪtɪŋ/ with emphasis on the first syllable and a "t" sound at the end. The word "prating" means to talk excessively or foolishly. So, "most prating" could mean someone who talks excessively more than anyone else. The correct spelling is essential to avoid any confusion in the meaning of the sentence.
The word prating is derived from the verb prate, which ultimately traces its etymology to Middle English and Old French. In Middle English, it was praten, meaning to chatter or to babble. This Middle English term was borrowed from Old French prater, with the same meaning. The word most is a superlative form, indicating the highest degree of a quality. So, most prating is a phrase that can be understood as meaning the highest degree of chattering or the most verbose.