Diction has a plethora of different meanings. Diction refers to the quality of speech when you can clearly understand what is being said. It's not about the manner of speaking or the use of specific words, but rather steady punctuation and pauses in the correct places. Diction is about the distinctiveness of speech.
The characteristic of tone refers to the essence of a language, which assists in recognizing words from each other. It is through a tone that emotions and other expressions are provided for the reader or the listener. Many languages have limited use of tones, such as Somali or Japanese.