[mbirth]

From their FAQs[1]:

> The overwhelming proportion of similar-sounding 3 word combinations will be so far apart that an error is obvious,

However, it continues like this:

> but there will still be cases where potentially confusable word combinations are nearby. Our Autosuggest feature actively intercepts possible errors or confusions and highlights other possibilities to the user, helping to identify what might need to be checked.

So they rely on auto-suggest and people trying all suggested alternatives.

[1] https://support.what3words.com/en/articles/3577589-how-are-t...