Bip39 Word List Cryptotag Some words are shorter than four letters, including the word “act”. Other words are for a longer time than 4 letters, which include “summary”. One set of mnemonic may be used to produce multiple addresses. This technique of building account was released in BIP32 & BIP39 https://worldlistpro.com/story20349068/seed-phrase-generator-and-checker-github-indicators-on-bip39-phrase-you-should-know