Bip39 first 4 letters https://collinmmss433.lucialpiazzale.com/from-concept-to-fact-generating-bitcoin-addresses-with-bip39 While it takes advantage of BIP32 system you could still import BIP39 seeds into Electrum wallet. Also other than BIp32 there is BIP44 version which some wallet use for your generation of seeds. What’s intriguing is that each different passphrase you use Using th... https://www.symbaloo.com/mix/bookmarks-xfkm