The sounds [w] and [j] are described as glides. They are both voiced and occur at the beginning of we, wet, you and yes. These sounds are typically produced with the tongue in motion (or “gliding”) to or from the position of a vowel and are sometimes called semi-vowels. 32 The Study of Language In some approaches, the liquids [l], [r] and glides [w], [j] are combined in one category called “approximants.”