BIP39 wordlists may seem arbitrary, but they are not - they are carefully chosen to reduce the chance of mis-specification. Words in a BIP39 wordlist are selected with the parameters in such a way that they don't have synonyms, don't have alternative spellings, don't have only 1 character variation with other words in the list, and aren't profane. These rules apply for every language. In addition, the first four characters of each word are unique to each wordlist, which is convenient when typing them into hardware wallets with limited input mechanisms, stamping them onto steel cards, or backing them up in any other form. BIP39 wordlists can be seen here: https://github.com/bitcoin/bips/blob/master/bip-0039/bip-0039-wordlists.md). Also, you don't necessarily have to remember this, but BIP39 wordlists have 2048 words in them. The reason for this is because it aligns with how BIP39 uses 32-bit blocks of entropy (random inputs) plus a checksum bit sequenced into a long binary string that is divisible into 11-bit numbers. Each of those numbers can hold up to 2048 bits. In short, 2048 words are all that are needed to achieve extremely high levels of entropy.