鼻化元音是发音时气息从口腔和鼻腔同时流出的元音。

国际音标及葡萄牙语都采用“~”标示鼻化。

A nasal vowel is a vowel that is produced with a lowering of the velum so that air escapes both through the nose as well as the mouth. By contrast, oral vowels are vowels without this nasalization. As explained below, nasal vowels that are distinctive or obligatory are of far more linguistic importance than whether or not speakers of a language tend to nasalize vowels in some instances. Relatively similar languages in the same branch of a language family differ on this point quite frequently throughout the world such as in Spanish and Portuguese.