The velum (it's normally spelled with just one 'l') is also known as the soft palate. It is the soft area in the back of the throat, beyond the hard palate, and consists of a covered sheet of muscle that ends in the uvula.
The velume is occasionally used in the production of consonants in English:
- "g" and "k" are the voiced and voiceless velar stops
- "ng" is the velar nasal
Other languages, such as German, make heavier use of the velum in consonant production.
English speakers do use the velum regularly in vowel production. When the velum is closed, the vowel is oral (the air comes out only through the mouth). When the velum is open, the vowel is nasal (the air comes out through the nose). An example of an oral vowel is the "a" in the word "bat"; an example of a nasal vowel is the "a" in the word "man." In English, nasal vowels regularly come before the nasal consonants "m," "n," and "ng."