Where is the stress in 'окна'? Here it sounds like it's on O but when I look it up it says that it's on the A. Is this a mistake on this site?
The stress is correct in the normal version, but in the slow version the software is confused as to which declension of the word it is supposed to speak and opts for the nominative/accusative plural where the stress is indeed о́кна. Can't get 'em all right I suppose :-)
In nominative and animate accusative the numeral “2” has two forms: «две» for feminine nouns and «два» for everything else:
- две подруги, руки́, судьбы́, ...
- два друга, стола, окна́, ...
The number 2 has a collective numeral form, «дво́е», which looks very similar to dvaja. While you're not required to always use it when talking about animate nouns, it doesn't work too well with inanimate nouns (except for pluralia tantum nouns). There are also some other restrictions, like you can't use it with feminine nouns, although the collective numeral «оба/обе» works fine with them.
«Два учи́теля» and «двое учителе́й» are very similar in meaning, but there is a subtle distinction in whether you view them as a single group or as a collection of individuals (hopefully that makes sense).
It is not very clear the explanation given in Tips and notes about how to fit the numbers with the nouns!
So one window is окно but two windows is окна for some reason. Don't know what gender this word is but okay.....
It's neuter, and окна is the genitive singular form. Neuter nouns in -о always end in -а in the genitive singular.
If I understood correctly, only after 2, 3 and 4 (and numbers that end in 2, 3 and 4).
And with numbers 5, 6, 7, and so on we use genitive plural - 5 окон, 10 окон, 100окон