Bip39 Ozon Some words are shorter than 4 letters, like the word “act”. Other words are longer than 4 letters, including “abstract”. 1 set of mnemonic can be utilized to generate multiple addresses. This process of producing account was introduced in BIP32 & BIP39 very long time in the past. https://bookmarktune.com/story18575311/12-word-seed-phrase-generator-with-balance-reddit-indicators-on-bip39-phrase-you-should-know