My Year Old Cat Has Stopped Meowing, Why?

Have your cat examined by a veterinarian to make sure there is no medical reason for the lost meow.  A good oral exam will be done to make sure there is no trauma or foreign bodies in the back of the throat.  Also the vet will listen to the lungs to make sure no signs of pneumonia or asthma are present.  Irritation to the nasal passage and throat may be making it uncomfortable or unable to meow normally.
Watch your cat closely to make sure it is eating, drinking, has a normal energy level, and is not coughing or sneezing.  If he is acting normally otherwise I would not be too concerned but better safe than sorry!

My 10 year old cat who is otheriwse healthy,has stopped meowoing development a nasty wheze in her chest,is lethargic and cannot eat properly,she is still communiaction with us and is also trying to cough something up, we have treated her for furballs but she seems to be getting worse, any ideas

It could have allergies call the vet and ask them how much benadryl to give our cat.