4E's Novelty Whisper Phones for Reading - Pack of 4 - Auditory Feedback, Hear Myself Sound Phone - Accelerate Reading Fluency, Comprehension & Pronunciation - Speech Therapy Materials Toys

No idea, that's gotta be frustrating for you and her. If it's a matter of hearing not just speaking, there are a tool I've seen speech therapists use: https://a.co/d/07ZNgF0A And you can diy them from PVC pipe.