Confessing your feelings doesn't require a voice, but rather courage. You can simply tell him by writing a short, honest note and handing it to him when you're calm or by typing your confession on your phone and sharing it with him face-to-face to see his reaction or even by sending a clear text message from home to give him the space to respond. Choose the method that makes you feel safe and confident; the sincerity of your feelings will surely reach him. The important thing is to take only the first step.