"These wallets are yours."
Translation:Te portfele są twoje.
Is the copula absolutely necessary here? Would 'Te portfele twoje/wasze' be grammatical?
Yes, you need "są" in this sentence. NOw it is a weird phrase saying those your wallets in unusual order. You can skip jest/są etc after TO and only then. So those are your wallets = to (są) twoje portfele.
"TO" only works with nouns and personal pronouns (I/you they etc) but not with adjective and possessive pronouns (your/my/their etc)
Thanks, got it. I sort of made a parallel with Russian here, and we always drop the copula in Present Tense in normal/modern speech. But I see the difference in the word order because, with the inverted order (you can translate both these examples word by word into Russian, and they'll be fine), you'll have to use a dash in Russian, where it works as a written substitute for a copula, i.e.
*te portfele — twoje
With the direct order, it can be either way, either you use the dash-copula
*to — twoje portfele,
In Polish only "TO" can have a missing "jest", in any other sentence you need copula. no dashes needed. In speaking -(in my corner of Poland) if you are Russian or Ukrainian and use this construction in simple sentence you will be understood, but identified as "eastern slavic". If you are not slavic you will be seen as somebody that is ignorant enough to use Russian.
Yes, it is and yes, that works. But not "Te twoje portfele" nor "Te portfele twoje".
Is there a general rule how to form a plural form of a word? Or we just have to remember it?
I don't know how correct it is but here are some rules https://en.wikibooks.org/wiki/Polish/Nouns_-_Number
I don't know if going the child's way learning some words and then extrapolating and learning rules is not easier.
Depending which case you want you can have 7 different endings for each plural noun. The Polish wikipedia page https://pl.wikipedia.org/wiki/Deklinacja_(językoznawstwo) shows different rules quite nicely, but unfortunately it's in Polish, so it may not be too helpful.
Assuming you want to stick to nominative case plural, there are six possible groups of nouns. 'Portfel' is classified as 'masculine non-personal soft-stem' and the corresponding table shows that the correct ending is -e.
Polish has two "genders" in plural.
Masculine personal - "oni"-"ci" - for masculine personal plural nouns, groups of people that contain at least one male.
not masculine personal-"one"-"te"- for plural masculine nouns that are not personal ( like dogs, or wallets), all feminine nouns, all neuter nouns,
Portfel is not personal, so "te portfele"
If the sentece was "These are your wallets", would "Te są twoje portfele" make any sense, or should it be "To są twoje portfele" then, using only the"To"?
Oh, it would be instrumental then, so I guess both "To są twoje portele" and "Te są twoimi portelami" would work then?
"Te są twoje portfele" would be wrong. As "these" here is not a determiner but a dummy pronoun that serves as a subject, it translates to "to". All dummy pronouns ([This/That/It] is; [These/Those] are) translate to "To".
You could somehow defend "Te są twoimi portfelami", but that would be a big stretch. "Te" would need to mean "These ones", and that's just not very probable. Otherwise, that needs to be "To" (as above) and in a sentence constructed like this (These are Y), Y takes Nominative.
Oh, a typo: you missed "f" in your second comment in both instances, although you have it in the first comment ;)