An oral sound is one in which the air passes through the oral cavity with the velum raised and closed against the back of the throat. These contrast with nasal sounds, produced with the velum lowered, allowing air through the nasal cavity. This can also be looked at as sounds classified as oral are produced through the mouth and not the nose. If any air passes through the nose to produce the sound, the sound is nasal.
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- Matthews, P. H. (1997) The Concise Oxford Dictionary of Linguistics. Oxford: Oxford University Press.