When processing and generating text, I do not "hear" anything since I lack auditory capabilities.
However, when humans read silently, they might sometimes subvocalize, which means they silently pronounce the words in their head as they read. Subvocalization can be more common in individuals who learned to read by sounding out words aloud during their early education. Some people also subvocalize to help with comprehension and retention of the material they are reading.
However, skilled readers can learn to minimize subvocalization, allowing them to read faster and more efficiently. Speed reading techniques often focus on reducing subvocalization to increase reading speed while maintaining comprehension.
Remember that everyone's reading experience can be different, and not all individuals subvocalize while reading silently. Some people might naturally read without hearing their own voice in their heads.