In phonetics, vowel reduction is the process by which vowels in unstressed syllables are pronounced with a shorter and/or weaker sound. This often results in the reduction of a full vowel sound to a schwa or other similar sound. Vowel reduction is a common feature of many languages, including English, where it can be observed in words such as "banana" (reduced second syllable) or "photography" (reduced third syllable). The change in the acoustic quality of the vowel can be a result of changes in stress duration, loudness, articulation, or position in the word.