M.B.
Have you and your doctor considered tubes? Both of my children needed them after having so many ear infections. As it turns out, their hearing was so muffled from fluid behind the drum that they just couldn't hear. It was really amazing after the surgery (It's a quick 15 minute surgery plus recovery time). Literally, my second son was forming new words that evening. It was just this amazing moment. You could see him listening and watching us talk and then repeat it! We also had friends that were having trouble with their 18 month old daughter walking. After having tubes put in she gained her balance quickly and was walking within a week. Please urge your doctor to refer you to an ENT to at least have everything checked out. Good luck!!