framework/helpers/BaseInflector.php
public static function variablize($word)
    {
        $word = static::camelize($word);

        return mb_strtolower(mb_substr($word, 0, 1, self::encoding())) . mb_substr($word, 1, null, self::encoding());
    }
public static function variablize($word)
    {
        $word = static::camelize($word);

        return mb_strtolower(mb_substr($word, 0, 1, self::encoding())) . mb_substr($word, 1, null, self::encoding());
    }
Same as camelize but first char is in lowercase.

Converts a word like "send_email" to "sendEmail". It
will remove non alphanumeric character from the word, so
"who's online" will be converted to "whoSOnline".
@param string $word to lowerCamelCase
@return string