@wolf480pl Well, in English it's more sporadic and irregular.
And in Polish (and Russian) it's just some declension magic %).
When a vowel is supposed to be said (in a written word), it is always pronounced in Russian, but can be turned into a schwa. So it's always there, but not reliably exactly what it is supposed to be.
"Yaponia" (Japan) is rather pronounced like "Yiponia".