t2wave said
Your question is vague at best. Are you asking how you should write thought of someone who has never had a voice? Or are you asking how that would be perceived. Theoretically a thought does not need a voice associated with it, that is a product of our mind putting what we hear with what we think. It is our way of making sense of the intangible. However, I find it unlikely that she would not, at some point, not have imagined some kind of voice. We as humans are social creatures and consciously unconsciously attempt to fit in. A person that is mute would most likely choose a voice that they believe is fitting for their personality or has some significance to them. Even the deaf, who cannot hear, can with practice speak their thoughts even though they've never heard a voice.
I actually have worked with many deaf people, who are mute and communicate with sign. I havr asked them how they think, and they say they just think in words, with a "mental voice". They found it hard to describe, because of course theu can't hear a voice, but do i0say that they have a voice in their head, same as you and me,
Sue isn't deaf, really, so she has heard voice, maybe she could have a voice she likes as her mental voice?