Slip over is a term used to describe the process of eliding, which is the omission of a sound or syllable when speaking. Elision is a common feature of many languages and is used to make speech more natural and easier to understand. Slip over is a form of elision in which a syllable is omitted from the end of a word or phrase. This can be done for a variety of reasons, such as to make the pronunciation smoother or to emphasize a particular point.