Assonance is quite a common language technique used mainly in poetry, but can be present in almost all forms of literature. It occurs when nearby or joining words have the same vowel sounds (e.g. tiny, ticklish tummies). It is used mainly to grasp the reader's attention to a particular phrase and it helps to exaggerate the meaning of that phrase. It may also be used for comedic purposes, or even to help a poem's general rhythm.