This is possible and is done using pinyin. The tone of the character can be highlighted in a different colour, such as CCEDICT and/or Pleco does. I have worked

This is possible and is done using pinyin. The tone of the character can be highlighted in a different colour, such as CCEDICT and/or Pleco does. I have worked on this before, but the sandhi and polyphonic characters kinda complicates it a little.