Bip39 Generatemnemonic Some words are shorter than 4 letters, including the word “act”. Other words are longer than four letters, which include “summary”. One particular set of mnemonic can be employed to develop multiple addresses. This technique of creating account was introduced in BIP32 & BIP39 while in the past. https://total-bookmark.com/story18434075/bip39-bip44-compatible-software-wallet-helping-the-others-realize-the-advantages-of-seed-phrase-generator