- Ist das dein Essen?
- Ist das euer Fisch?
What is different between the function of "dein" and "euer" in these two sentences? Is it okay if I replace "dein" with "euer" in the first sentence?
I would say we use both.
There is the synecdoche: "Der Fisch [singular, but we mean all fish] hat Schuppen" = Fish [pl / in general] have scales.
But there is also your example, the use as an uncountable noun as in "Ich esse Fisch". So you can use it in the same way as in English for the dish "fish", but not for the living animal.
You are right. We can say We eat fish and mean we eat fish in general unimportant which one or how many fishes. We also have a singular for fish and a plural: der Fisch, die Fische
The possessive pronoun Dein is normally used for to say for the 2nd person singular that the fish is owned or belonging to the person. Like: "Du hast Deinen Fisch noch nicht gegessen." or "Dein Fisch ist nicht frisch." For plural or the midage majestic plural we use Euer: "Ihr habt euren Fisch noch nicht gegessen." or "Euer Fisch ist nicht frisch."
Usually, it is like many said: "dein" is singular (for one person), "euer" is plural (for several persons) and they cannot replace each other. But additionally, "euer" can be used as a very formal singular version: "Euer Essen ist fertig, eure Majestät." But personally, I never had to use that version, and I would not expect anybody to every address me like that. (And if someone expected me to address her/him like that, that would feel very very arrogant to me.) Maybe if you address some politician like a minister or president, or the head of a huge company. But even than, personally I would use the normal formal variant "ihr" instead. ("Ihr Essen ist fertig, Frau Bundeskanzlerin.") and for several people: "Ihre Essen sind fertig, ..."
(I'm a native German.)
Did that help?
I will follow the order of the personal pronouns for you: () = the objects in plural 1st person singular: mein Essen, mein Fisch (meine Essen, meine Fische) 2nd person singular: Dein Essen, Dein Fisch (Deine Essen, Deine Fische) 3rd person singular (a) he; b) she; c) it): a) sein Essen, sein Fisch (seine Essen, seine Fische) b) ihr Essen, Ihren Fisch (Ihre Essen, Ihre Fische) c) (like a))
1st person plural: unser Essen, unser Fisch (unsere Essen, unsere Fische) 2nd Person plural/ plural majestic ( plural majestic is today mostly used in theater or comedy): Euer Essen, Euer Fisch (Eure Essen, Eure Fische) 3rd person plural: Ihr Essen, Ihr Fisch (Ihre Essen, Ihre Fische)
In German we use together with the cases (advanced I would say): 1st person singular (I/ ich): mein, meine, meiner , meines, meinem, meinen 2nd person singular (you/ Du): Dein, Deine, Deiner, Deines, Deinem, Deinen 3rd person singular he/ er: sein, seine, seiner, seines, seinem, seinen she/ sie: ihr, ihre, ihrer, ihres, ihrem, ihren it/ es: (like he)
1st person plural (we/ wir): unser, unsere, unserer, unserem, unseres, unseren 2nd person plural (you/ ihr): euer, eure, eures, eurem, euren, eurer 3rd person plural (they/ sie): ihr, ihre, ihren, ihres, ihrem, ihrer
It is difficult in the beginning but if the start is made with enough examples you learn to see a rhythm in it.
A warning: Do not mix up the personal pronoun rules with a salutation for the plural majestic:
for example: "Your highness may I bet for the permission to speak?" = "Euer Hoheit darf ich um die Erlaubnis bitten zu sprechen?" (masculinum e.g. a king) or "Eure Hoheit darf ich um die Erlaubnis bitten zu sprechen?" (femininum e.g. a queen). And if you talk with someone else about them it would change this way: "Their majesties may not be interrupted." "Ihre (wrong but famous for to show a person that tries to act educated but is not: "Ihro") Hoheiten dürfen nicht unterbrochen werden." or singular: "Ihre Hoheit darf nicht unterbrochen werden." (femininum) or "Seine Hoheit darf nicht unterbrochen werden." (masculinum) - But this is not possessive pronoun. It is the plural majestic.
sorry for interrupting but it is both. You may not say "Dein" in the formal language. It is the rule for "siezen und duzen" in German:
You may only adress someone who allows you to be informal (friends, familymembers) with: Du, Dich, Dein... All others like strangers, bosses, chiefs, persons you meet the first time, older people... have to be adressed formal like the 3rd person plural. For example:
If you see someone looses his or her smartphone in the subway you could say: "Verzeihung? Sie haben Ihr Telefon vergessen." But you should not say: "Verzeihung? Du hast Dein Telefon vergessen" and in the medieval it was formal to use "Euer", "Euch"... to talk to someone who is at least on the same status or higher in society.