Hearing one's thoughts in someone else's voice out loud can sometimes be a normal phenomenon and not necessarily indicative of a mental health issue. Many people may occasionally have fleeting experiences like this, especially during moments of stress or fatigue.
However, if this becomes a persistent or distressing occurrence and starts to interfere with your daily life, it may be worth discussing with a mental health professional. Hearing voices that others don't hear could be a symptom of various conditions, such as auditory hallucinations, which can be associated with psychiatric disorders like schizophrenia, bipolar disorder, or certain neurological conditions.
If you have any concerns about your mental health or are experiencing distressing symptoms, I encourage you to seek guidance from a qualified healthcare professional who can provide a proper assessment and support. They can help determine the underlying cause and recommend appropriate treatment if necessary. Remember, it's always essential to prioritize your mental well-being and seek professional help if needed.