This is similar to Generate pronounceable passwords with a twist, it follows BIP39 conventions used on the Bitcoin blockchain (though arguably Monero has them bested). There are two JavaScript implementations linked from the BIP, one of which is used by blockchain.info according to the doc.
Wordlists are provided in 8 languages currently and this approach should leave little room for dubious errors. So rather than a password like l33th4x0r we would instead be able to produce a pronouncable password of the XKCD variety but without the humorous snark.