The answer to 'cockroach scratching sounds' is that cockroaches can make a scratching or rustling sound as they move around. This is typically caused by the cockroaches' hard exoskeletons rubbing against surfaces as they crawl. Cockroach scratching sounds are a common sign of an infestation, as they indicate the presence of these pests in your home.
Cockroaches are nocturnal, so you're more likely to hear the scratching sounds at night when they are most active. The sounds may come from behind walls, under appliances, or in other dark, secluded areas where cockroaches like to hide. If you're hearing these noises, it's a good idea to inspect for other signs of a cockroach problem, such as droppings or egg cases.