When you you have aspiration pneumonia you'll have a cough that produces thick and discolored sputum or mucus when you cough.
You'll cough up some sputum that is discolored and thick and the sputum or mucus will also have a foul smell to it if you do have aspiration pneumonia.
But the only way to confirm if you do indeed have aspiration pneumonia or any other type of pneumonia is through having a chest x-ray that confirms the diagnosis of the aspiration pneumonia or other pneumonia.
Pneumonia can be deadly if not treated especially if the pneumonia is a more severe pneumonia so you should always get checked out and treated just to be safe.
The doctor can confirm through an X Ray if you do have aspiration pneumonia which is the only way to really know for sure if you do have pneumonia.