Talk to Speech Therapist on Babyish, High Pitch Voice And Processing Delay

My 10 years daughter thinks in mind that she is speaking loudly or answering, but others feel her mute or slow She thinks in mind that she is speaking slowly, but others feel her loud She thinks there is some voice in back of her mind. That voice is something noise. She has Processing Delay in Speech-Takes time to respond. She speaks in babyish and high pitch voice in School and outside with others apart from family. She speaks normal voice at home. Where can I get proper diagnosis and treatment? Any treatments? What can be root cause of undelying issue? is this neuro issue or voice disorder or what? Anyone experienced same issue? Appreciate your thoughts and advice