An algorithm for encoding a word so that similar sounding words encode the same. The first letter is copied unchanged then subsequent letters are encoded as follows:

        bfpv          -> "1"
        cgjkqsxzç -> "2"
        dt          -> "3"
        l          -> "4"
        mnñ          -> "5"
        r          -> "6"

Other characters are ignored and repeated characters are encoded as though they were a single character. Encoding stops when the resulting string is four characters long, adding trailing "0"s if it is shorter. For example, "SMITH" or "SMYTHE" would both be encoded as "S530".