Not hearing or not listening.

Some parents find themselves trying to work out whether their child is not hearing or just not listening. Because............. the child does not stop when they are called, or does not do what s/he has been told to do. Or does not in some way, indicate that s/he has heard.

But there are other factors that come into play. 
Ask questions such as: 
Are they concentrating so much that they shut out all other sounds?
Are they focused on what they are about to do? I.e. the plan in their head.
Do they experience a delay in processing the auditory information?
Do they have a strong need to follow their own internal agenda and lack the ability to quickly change?
Do they have an emotional need that affects their ability to process incoming auditory information?
Is the short term or working memory such that they forget immediately?
Is you child super sensitive to some particular sounds?

In a general way you already know whether your child is hearing. You will have noticed whether s/he turns towards sounds. You will have noticed whether they ask "what's that?" when a sound is heard.
You will have noticed whether they respond to music in any way. You will have noticed whether they answer you in different situations.....such as face to face conversations when the attention of both of you is focussed on the other.
So if they can hear, then the issue may be one of the other possibilities.

Processing delay:
A delay in processing auditory information can be variable which makes it difficult to recognise. The delay may be a second or longer or of different lengths of time at different times. Personally I sometimes experience a delay. For me it is like this.....Someone says something to me and all I hear is a jumble of sounds. On occasion, by the time i say "pardon" I have got the words. And sometimes I really do need the words to be repeated.  If you suspect that your child has an auditory processing delay, give them time. Wait quietly and patiently with your attention lightly focussed on them so you can observe when they click.
Do not repeat the sentence in different words. Often as adults, we do this. Perhaps we think it will help the understanding if we say the instruction again in different words. But for a child with delayed processing this compounds the issues because now they have another set of words to process. Wait for a few seconds and then repeat using the same words.

Memory Issues:
For some children, their auditory memory does not work well. We have strengths in different information systems and your child may be stronger in the visual system than the auditory. And of course, verbal information is gone the moment it is said. It relies on a quick auditory memory for the child to be able to follow an instruction said once. Repeating the instruction can be helpful. Using visual prompts can be really helpful. Even drawing a plan on a piece of paper. The act of drawing and talking it through, will give your child time to process the auditory information at the same time as giving him/her the visual information. Visual information can be referred to again and again as needed.

Attention:
If a child is concentrating solidly on a task or game, find a technique that you can use that gains their attention  gently. Maybe discuss it with them, that you will use a signal. Like a classroom teacher doing her pattern of clapping! 

Own agenda:
According to how your child's brain is wired, they may quite strongly follow their own plan and find it difficult to change from their plan to someone else's plan. Therefore they need a warning or preparation about changes.....a signal needs to be given, and time for the child to unwind from their plan. A visual plan is helpful if possible. Their plan might even involve a toy that another child has in their hands. So strife can easily arise.
​
Emotions:
If a child is having a time of major life change, or major steps (e.g. starting school, shifting house) their ability to process auditory information can be affected. They may be putting unconscious effort into whatever they are doing which means they have less capacity for listening and taking on board other instructions.

Sensory Issues:
There may be a difference in how your child integrates the auditory information. S/he may be super sensitive to some sounds. This can create anxiety about all sounds, and induce a fear of certain sound making things. This can also mean that the ability to integrate auditory information is uneven....i.e. some sounds are heard as very loud and other sounds are heard very soft or not at all.

So there are many factors affecting why your child is not responding to verbal instructions or not listening to you.