an example of this would be the japanese words "chizu", which has a short vowel (a vowel spoken for a short time), and "chīzu", which has a long vowel (a vowel spoken for a long time). the only difference that can be heard is how long the vowel "i" is spoken. the amount of time the vowel is spoken could create two entirely different words. "chizu" means "map", while "chīzu" "cheese".