A combining vowel is often added to a word root.What is a vowel,and why would such a thing be added to the word root?

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A vowel is a letter that represents a speech sound made with the vocal tract open.In medical terminology, a combining vowel (usually "o") is added to the word root to make it easier to pronounce when combined with other word elements such as prefixes or suffixes. The vowel also helps to separate the word root from the other elements and maintain the word's meaning.

A Combining Vowel Is Often Added to a Word Root