Think of a speech as a piece of music.
Like a piece of music, it has melody, harmony and rhythm. Melody rises and lowers according to the notes, i.e. the words. Harmonies are a blend of facts and stories blended for meaning.
And tempo, fast or slow, matches mood and meaning. Put more simply, every good speech must have its own signature, a rising and falling according to meaning and a tempo owing to emphasis.
Speech delivery, like playing an instrument, is an art that can be mastered; it simply takes a willingness to try and a commitment to speaking in public whenever you have the opportunity to do it.