mein, dein, sein: the possessives and their endings
CEFR A2 · part 1
edumaterial's parts within the level. The European framework does not subdivide them.
The dative: dem, der, dem and den + -nPutting any phrase into the dative: seeing that the marking travels in the article…The seven prepositions that take the dative: mit, nach, aus, zu, von, bei, seitAutomatically putting whatever follows these seven into the dative, without stopping to…Verbs that take the dative: helfen, danken, gefallen, gehören, schmeckenRecognising the dozen German verbs that take a dative rather than a direct object, and…The Perfekt with haben: the past that people actually speakTelling any past event the way Germans do when they speak: haben conjugated in second…The Perfekt with sein: moving and changing stateDeciding in a second whether a verb takes haben or sein, using the two questions that…The participle: ge- -t, ge- -en, and the ones with no ge-Building the participle of any verb: the ge- -t mould for regular ones, ge- -en for…The rule, in three lines
A possessive carries two decisions inside it and they are independent. The STEM is chosen by the owner: mein, dein, sein for him, ihr for her and for them, unser, euer, Ihr for you formally. The ENDING is chosen by the thing owned, and it is exactly the same as kein's: meine Schwester because Schwester is feminine, meinen Bruder in the accusative, meinem Vater in the dative. Learn one table and you get both.
The usual slip. Making the possessive agree with the owner, as if it were your language's «his/her», or making it agree only with the thing owned. It is both at once: in meine Schwester, mein- is because the owner is me and the -e is because Schwester is feminine. And the costliest mistake is using sein for everything: sein Haus is HIS house, and hers is ihr Haus.
Why it catches you out. English possessives never change: «my» is «my» in front of anything. So the endings are pure extra work, with no model to lean on. The one thing English does have that helps is the his/her split —German's sein and ihr are exactly that— while Spanish, Portuguese and Italian all have to learn it from scratch.