Quick answer
Unstressed о is pronounced like a: молоко́ = “malakó”. Unstressed е and я weaken towards i: сестра́ = “sistrá”.
The о rule (akanye)
| Written | Spoken | Why |
|---|---|---|
| молоко́ | malakó | only the stressed о is a real o |
| хорошо́ | kharashó | same |
| Москва́ | Maskvá | the о is unstressed |
| окно́ | aknó | unstressed о at the start too |
The е and я rule
This is why a Russian word you know in writing can sound unrecognisable: the vowels you were expecting are simply not there.
Two more habits
Final consonants go voiceless: хлеб sounds like “khlep”, друг like “druk”. Г sounds like в in the endings -ого and -его: но́вого = “nóvava”, сего́дня = “sevódnya”.
The good news
Reduction follows the stress, which you already have to learn anyway. Get the stress right and the vowels around it fall into place almost automatically.
Typical mistakes
Pronouncing every о as “o”
only the stressed one
It is the single clearest marker of a foreign accent.
сего́дня with a hard г
“sevódnya”
The -ого / -его ending is spoken with в.
Check yourself
How is молоко́ pronounced?