We play with with a least twice daily. He plays with the other cat. He is
neutered. The Vet says there is nothing wrong with him. He is perfectly
healthy. we give him tons of love. The other cat is more independent and so
this cat gets the most of our attention.

I see below Manx is the breed.

I found this as a specific on a manx who acted like this:  "You need to take
her to a vet. Most Manxies won't meow at all. Or least ours didn't. She
could be hurt inside or have worms if she's been outside. And if she's gone
from outside to inside only she may want out. Badly. They can be obnoxious
when they want something. That was another of Bob's traits. She was rotten
and always attention starved".  I do not know if this person was right, but
saw several others who had had similar reactions by their cats who it turned
out had worms.

Apologies but I didnt read all your messages so do not know if you have
already had this ruled out by a vet.

Here's a few other things I saw related, but they were not 'manx specific'.
They may help?

Feed on a regular basis.
 a..
 Try and feeding your cat at set times/regular intervals so they can
anticipate when they're next going to eat. You can also try leaving down the
dry cat food/biscuits so that your cat can nibble whenever they get hungry.
However, if you cat has a tendency to over-eat, this may not be wise.

 b.. Install a cat flap.

 Most cats can never make up their minds if they want to be in or outside.
My cat is in heaven during the summer when I can leave the back door open
and he can wander in and out at much as he pleases. If your cat is always in
and out, a cat flap is a great option. They are fairly cheap and easy to
install and you buy ones which have magnets on them so only YOUR cat can get
in.

 c.. Play.

 Some cats meow a lot because they want some attention and affection.
Stroke and play with your cat often to keep them from feeling lonely or
neglected.

 d.. Discipline.

 Don't let your cat drive you round the bend with excessive meowing - take
charge. You can either ignore them which will eventually make them stop if
you don't give in (very hard to do!) or you can try the old favourites of a
squirt with a water spray or a firm 'NO' and a clap of the hands. Eventually
your kitty will realize that constant meowing will get them nowhere. Please
ensure you remember to praise your cat and give extra attention to them when
they're not meowing.

(I'm not totally in agreement with the water squirt as you cn cause your cat
to develop other problems with this sort of negative behavior.  If you do
decide to try the spray route, have been told the nest way to go about it is
to spray just the toes and in such a way that they can't see 'you' do it,
such as from under a door with you on the other side).

One memory spark, one of the cats I had long ago, would meow quite loudly
all night if I didnt let her sleep with me.  Now, I didnt mind a cat
sleeping with me so was able to fix it that way.  Do be sure to rule out
worms first!

Oh on wormers, you may already know this but another may not.  It's best
(really) to have the vet check for which type of worms first.  Reason is
they dont all react to the same 'over the counter' meds and you could be
just making the cat sick with OTC stuff if it's heartworms or some of the
others.

Best I can do here as I know little more.

We need more info, having kids in the household might be a "factor"...

And "yelling" and "spraying with water" is *extremely* counter -
productive...

Here is what I would do. :)

In fact, I did this with my first cat when she engaged in a variety of
behaviors
(including loud vocalizing) that were clearly intended to get my attention,
and
defied medical or other explanation.

Whenever she howled, I went to her, picked her up, and loved all over her,
talked to her, ruffled her fur, hugged her, kissed her, scratched her ears,
turned her over and held her like a baby, put her up on my shoulder and
walked around with her, sang to her, and petted her all over.

She stopped howling pretty soon thereafter.