which is pronounced pretty much the
way we pronounce the letter p. There's some air behind it, but not much. It's
romanized as p
This letter,
has an extra-strength puff of
air behind it. It's romanized as p'. You can think of the apostrophe as that
puff of air.
And this letter,
has no air; it's the p of spin.
Your throat sort of tightens up when you say it; the technical term for this is
that the letter
is glottalized. It is
romanized as pp.