docs: function(pinyinWithoutTone)
          {
              var newToneMap = {};
              for(var i in toneMap) newToneMap[toneMap[i]] = i;
              return (pinyinWithoutTone || '').replace(/[a-z]\d/g, function(m) {
                  return newToneMap[m] || m;
              });
          }