In audiological practice, measuring how well a patient understands speech is essential for properly diagnosing hearing loss and evaluating the real-life benefit of a hearing aid. Currently, the gold standard is asking the patient to repeat speech that is presented via a loudspeaker. This gives reliable results in adults with normal cognitive function but cannot be used in certain groups such as young children, people recovering from a stroke, people in a coma, or people with dementia. Therefore, we developed a brain-computer interface (BCI), CORGEE, for real-time EEG-based hearing diagnostics based on brain response measurements while listening to natural speech. We have recently shown that our method is effective in measuring speech intelligibility and hearing aid benefit for hearing-impaired children. Our BCI holds great promise as a tool to be used by hearing care professionals in daily clinical practice.