My son suffered from the same problem when he was about seven. We suspected a hearing problem as he too had suffered from colds and earaches and was mis-hearing words.
Luckily, a good friend who worked as a practice nurse for an ear, nose and throat specialist and she arranged for our son to be seen by him. Glue ear was diagnosed (narrow tubes had become blocked after repeated colds) and Peter had gromits inserted. The difference was instant and amazing.
Apparently hearing can vary as there can be air bubbles in these tubes which allow them to hear occasionally.
Frighteningly I was also told that had the operation been delayed much longer he would have suffered some permanent hearing loss.
Margaret Kent 252 Inkerman Street, Preston