Du gefällst mir.
Please why does this mean
I like you.
Not
You like me.
?
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Sign up to join this communityIf you look up "gefallen" in a German-English dictionary, you'll find (among other words) "to please".
So "Du gefällst mir" = "You please me" = "I like you".
If you're looking for a direct equivalent of "to like", you'll find "mögen".
"I like you" = "Ich mag dich".
As was already pointed out, it's a dative construction - while it can be translated literally, the best thing to do is to just memorize that certain verbs are used in this way which may confuse native speakers of English, but it is worth pointing out that this sort of construction is not exclusive to German.
Let's look at the translations of "I like this song" in various languages:
Spanish "me gusta esta canción":
where me is the dative of yo ("I"), and esta canción ("this song") is in the nominative case and the verb gustar takes a 3rd person singular ending
Russian "мне нравится эта песня":
where, again, мне is the dative of я ("I"), эта песня ("this song") is in the nominative case and the verb нравиться takes a 3rd person singular ending
Japanese (私は)この歌が好きです ([watashi wa] kono uta ga suki desu):
the nominative particle ga relates to kono uta ("this song"), while the topic particle wa relates to watashi ("I") (although it would usually be omitted unless there is need for special emphasis) and suki (which together with the copula desu is the verb of the sentence) is actually a "nominal adjective" corresponding roughly to the odd-sounding English passive "[is] liked"
This is not exactly a dative construction, but it still illustrates that other languages might use subject and object in an opposite fashion.
What I intend to say is: when learning a foreign ĺanguage, one of the most important things to understand is that most things can (or should) not be translated in a word-by-word fashion but that it is much more important to understand the grammatical features and constructions of the foreign language.
The old (and long forgotten) meaning was (in modern German):
Du gefällst mir. = Du bist mir (durch das Glück, durch ein Los) zugefallen.
This means:
I won you by luck, by fortune.
or shorter:
You are mine.
But over the centuries that possessive meaning turned into:
I wish, you were mine.
or shorter:
I like you.
But said in the beginning: That possessive meaning of »Du gefällst mir.« has been forgotten centuries ago.
"Gefallen" uses the dative case. It is a verb that "reverses."
The usual construction would be something like "Du gefälllst mich" (accusative). That would mean, "You like me." Except that this construction doesn't exist.
But the construction for this verb is more like, "you are pleasing to me." The "to me," uses the dative construction "Du gefällst mir."
This reverses or "turns around" to mean, "I like you."