Hi
@moonbeam.
What you're dealing with is nowadays called developmental trauma or relational, and a common symptoms sufferers deal with is the fear of speaking.
One of the problems with modern diagnostic methods is its emphasis on symptomology (such as your fear of speaking) which often lead to a diagnosis of "social anxiety disorder"; but this practice is far from helpful as it obscures the traumatic origins of the problem.
People aren't born with a fear to speak: they're brought to that state through the types of experiences they have with others.
No doubt, bullying would be a common etiology for a person who experiences an inability to find "His voice", as, when you're being bullied, part of the problem is the debility one experiences in speaking up.
This disorder is also called "complex trauma" to differentiate it from the "shock" traumas experienced as adults. Complex trauma tends to follow on the heels of adverse early-life relationships with an attachment figure, thus, people who go on to developing a fear of speaking likely had a parent who regularly induced in them a feeling of anxiety. From here, to the school environment, research has shown that it is the kids who are prone to anxiety (who developed these tendencies as a consequence of the relational experiences with an inconsistent, abusive or negligent primary caregiver) who become the targets of bully's (who are themselves the product of a different type of abnormal developmental context)
While I would recommend you contact a psychodynamic psychotherapist (that is, avoid CBT therapists who do not utilize a psychodynamic framework) I can give you some pointers to help you figure out what you're feeling.
First of all, these experiences you're having aren't permanent. They are something you can sometimes feel, but you can, with practice, learn to influence how you feel in these situations.
Things to pay attention to:
Ask yourself, what am I feeling? Do I feel connected to my body? For example, do I feel an anxiety in my throat region? A flightiness in my legs or chest? Am I obsessing about my voice? Am I anxiously anticipating conversations and the effects they have on me? Do I pay attention more to the other person than the remain conscious of my own emotions?
What you're experiencing in these situations is classic PTSD hyper-vigilance and fear. The fear is the fear of negative feedback. And your protective mechanism is to obsessively "watch yourself" before you speak.
First, disengage from the thinking. The thinking is itself the opposite of feeling. Feeling, and emotion is what you want, but when you're "in your head", you've become disembodied. The psychiatrist Richard Chefetz calls these sorts of obsessions "the poor mans dissociative process", in that you think as a way to defend yourself from feeling.
Whats very important, also, is to get embodied - which isn't easy for someone who is dissociative/obsessive. This requires whats called "interoception" - scanning your body. The brain is connected to the body (peripheral nervous system) through the vagus nerve. And the vagus is the portion of our neuroanatomy which governs our homeostasis - which includes both our bodily AND our social/emotional experiences.
Recent advances in neuroscience and the science of psychotherapy have given us tremendous insights into how the mind can regulate its physiology by focusing on breathing. When we inhale, for instance, we induce an adrenaline response: we all know this feeling. But when we exhale, depending on how we do it, our body can either 'contain tension' by breathing in a shallow and rapid manner, or, we can extend our exhalations, and in the process, induce the release of endorphins, which relax the muscles, slow the heart beat, and in turn, permit a more relaxed and focused way of relating.
Focus on your breathing, allow yourself to experience a deep exhalation before speaking. Relax INTO this feeling, and then speak. Speak from your body - and not your thought. To begin thinking is to reactivate the hyper-vigilant processes that keep your body in this sort of tension. The idea is to relax, feel the goodness of the feeling, and to speak from that feeling.
Hope this has helped.