I'm not conscious of doing so, though I often subvocalize when reading. You can try humming (vibrating/pulsing the voice box area) or listening to brainwave ent

I'm not conscious of doing so, though I often subvocalize when reading. You can try humming (vibrating/pulsing the voice box area) or listening to brainwave entrainment audio to lower the amount of subvocalization. Brainwave entrainment audio should also help you better concentrate/focus and relax.