Solmization, I think is maybe what you are looking for? It is where you sing a song using the Solfege (Do/Re/Mi....)? Though I wouldn't say that it is the sam

Solmization, I think is maybe what you are looking for? It is where you sing a song using the Solfege (Do/Re/Mi....)? Though I wouldn't say that it is the same as "sight reading" -- but maybe "sight singing"?