Diction and tone might actually have some kind of connections, but the two terms are not totally the same. The term diction does not totally refer to the way someone pronounces words, how he pauses, and the tones used; it also refers to the choice of words and the vocabulary used by a person when writing; although the term diction has so much to do with your speech than your writing.
There are different kinds of elements under diction; they include; utterance, verb, phoneme, inflection, conjunction, connective, verb. So, the concept of all these elements must be mastered to have the right diction. On the other hand, the tone is usually explained as the pitch used in a language.
Most times, tone refers to the way the feelings and attitude of a character are communicated by a speaker or writer. In some languages, tones are used majorly to determine the meaning of a particular word meaning a word can have different tones.