An 18-word mnemonic phrase will increase stability by including more words on the sequence. Here’s an instance: Standard recovery phrases use a selected list of 2048 words next the BIP39 standard (Bitcoin Improvement Proposal 39). You may confirm if your words are Element of the BIP39 list using these sources: https://bookmarkforce.com/story19695907/considerations-to-know-about-bip39-word-list-pdf