The repetition of sounds can be used in both essay and poetry to emphasize certain words and so to make a description more interesting and effective. Alliteration, assonance and consonance are the names given to three different patterns of sound repetition.
Alliteration is the repetition of initial constant sounds. Some familiar examples of alliteration are the phrases fast and furious and tried and true.
Assonance is the repetition of vowels sounds. The short /i/ sounds for example is repeated in the phrase hit and miss and the long /e/ sound is repeated in the phrase free and easy.
Consonance is the repetition of final consonant sounds. Near and far and stroke of luck are familiar examples of consonance. Occasionally, one of these patterns may be used in longer phrases and even throughout a sentence or paragraph. Alliteration, assonance and consonance must be used with care, however. When they are overused in a sentence, they may detract from the meaning of the sentence. The reader may become so interested in the repeated sounds of the words that the message of the words will be lost in addition, overuse of pattern these patterns of repetition may sometimes make a serious piece of writing sound silly. Alliteration, assonance or consonance then should be used occasionally to emphasize certain words, but only when that pattern of repetition can be achieved without sacrificing the clarity of the writing
In summary, alliteration is the repetition of initial consonant sounds. Assonance is the repetition of vowel sounds. Consonance is the repetition of final consonant sounds.