I love it when Elrond is portrayed as someone who is a little bit incomprehensible to most of the elves at first. Not even just because he's a half-elf, but because he reminds them all of so many other people, and that layering can be kind of jarring.
He sings beautifully, with a voice that sounds like no elf or man, and it reminds many of the Sindar of Luthien. It reminds some of the Noldor of someone else, another singer with raven-dark hair and starry gray eyes.
The braids he does his hair in– and he always keeps it braided at first, because letting it run loose is another thing that makes people whisper of Luthien– are in the traditional Noldor style. The survivors of Gondolin love that; Turgon always wore his hair in classical styles too. The other part of the House of Finwe that clung to traditional braids goes unmentioned. But everyone knows.
And he was clearly taught about court manners; taught to be gracious and charming, and a very good listener. The elf who could have taught Elrond those things is usually skipped over entirely, in favor of those reminiscing about Idril's graceful poise or Melian's endless patience.
He looks very much like Luthien, but there is a particular Finwean sharpness in his facial structure; something that makes him look a lot like Fingolfin, as well. Fingolfin looked very much like his father. And his older brother.
His smile is just like Earendil's (whose smile is just like Tuor's), and his strange, birdlike laugh is from Elwing. He fights and writes with his left hand– but then, so did Earendil, because while all elves are right-handed, not all humans or half-elves are. He eats no meat– just like Beren, they say, but the way Elrond tells it the choice had nothing to do with that history. There is ainuric power in him and something very human in the set of his shoulders. The flowers grow around any place he stays long enough. He gets sick in a way no elf, and certainly no maia, ever would. His accent is odd, and archaic, and changes noticeably when he's too tired to obscure it. His mannerisms are a mixture of about twelve people, almost all of whom are dead, and several of whom are not spoken of by the time he shows up in Gil-Galad's camp.
And the reflections of Elrond unsettle a lot of people; because one moment they see a fallen hero or loved one, and the next they see the person that took them. Or perhaps someone else, that they never knew at all. There is reverence and fear and uncertainty. It's messy.
Elrond himself is coming to peace with this by the War of Wrath. There is love in carrying the parts of your ancestors with you, even when they aren't around any more. And he knows better than anyone that he is always himself, first and foremost. Still, it takes everyone else a while to stop seeing a ghost and start seeing Elrond.