As somebody who grew up on the anime, it's Pok-A-mon. It's in the theme song!

By pokemon, you mean pok- eeeee- mon.

Right?

It think it's rare thing someone pronouncing it like that.

Maybe those who say Nai-kee (which in my surprise is the proper pronunciation) , instead of Ni-ke. 

Is this "A" a schwa sound? Anyways, where I live, we  pronounce it with a /ɪ/ sound, like in kill, bill, etc. Also, we don't pronounce the /tʃ/ sound in the ch part of Pikachu like in the word cheese. Instead, we use the /ʃ/ sound, like in shower

What the heck?

Sounding almost like picasso.

The "A" is like how you would say the letter "A" in English. Not quite a schwa. It's like how you would say "Pay", "Day", "Gray", "Hey", etc.

I like phonetics

You're telling me there are people who say Pok-/eɪ/-mon? LOL

So, a like a Greek epsilon.

While the letter a in english , which is alpha in greek, sounds mostly like the Greek epsilon and e has the same shape with ε (epsilon).

However,  in many English words e sounds like an A.

Got perplexed with what I wrote, I need to go to bEd After that.