# How do I say the luminosity class aloud?

I have need to say the spectral type of a star for a poster presentation I'm making, which includes the luminosity class. However, I've been unable to determine the standard way of doing so, and searching the internet has been fruitless. The spectral type is M4 V. I don't know whether I should say Em four vee or Em four five. I thought the first sounded better, but then I thought, "What if it were M4 III instead?" After all, Em four eye eye eye is a bit clunkier than Em four three, and consistency is important. Is there a standard way to say these aloud, and if so, what is it?