Young.
1.
When Spock applies to leave Vulcan for Starfleet, he is twenty-eight, which makes him a well-grown adult in human terms, but still a teenager by Vulcan standards.
2.
Earth is not particularly strange for Spock. He never accompanied his father off-planet on a diplomatic mission, nor did he ever follow his mother home on visits to the surviving aunt on Earth, but he did, before applying to Starfleet Academy, take a trip to an environmental diversity pod maintained to give the appearance of Earth. Constructed underground to shield it from the extreme variations of Vulcan temperature, it also had reduced gravity, lighting to simulate a single yellow sun, and much higher air humidity than anywhere on Vulcan. Spock noted these differences, tested his muscles against the strange air and gravity, then went home.
"How did you like it?"
He had been taller than his mother for over a decade, and Spock was quite used to looking down a bit. "Like?" He said lifted his eyebrows at her. Are you referring to the Terran sense of enjoyment?"
She smiled and put warm flatbread and cold chickpeas on the counter in front of him: his father was two weeks into a six month trade mission to the Andorians, so they ate alone, in the kitchen, with the evening wind rattling down the canyon and making the windchimes bang against each other.
The first time he had hummus on Earth, Spock became so violently homesick that he thought he had taken ill.
3.
The first time Spock has hummus after his mother dies, it is at the reception following the award ceremony promoting Jim to captain.
Spock had been occupied for thirty-two hours previous working on getting the Enterprise in shape to fly for her next mission, due to begin in forty-six and a half hours. There were questions regarding the organization of berths and trilinium distribution systems that had required his personal attention, so he had not eaten for -- for some time.
All of the other food contained meat or was otherwise unpalatable.
Spock expects to feel emotion. In fact, he braces himself for emotion. Instead, nothi --
4.
The first six years that he spent on Earth, he found himself lonelier than he had been on Vulcan. Vulcans had made it a habit to exclude and let Spock know that he had been excluded. The mixed society of Starfleet made it a habit to include and let Spock know that he had been included, but it still worked to remind Spock of how different he continued to be.
5.
When Spock was two and a half years old, Sarek came home from a short diplomatic trip to find Amanda waiting for him in the front hallway. Spock was asleep in her bare arms; his cheek rested against her neck, and his cheeks were faintly green from how deeply he was sleeping: it is the way of humanoid babies the universe over to sweat in their sleep.
"You will have to stop doing that eventually," Sarek said, softly, coming to put his hand on Amanda's shoulder. "It does no harm now, but in a few months, his telepathy will develop, and until he learns to control it, you should not bring his bare skin to yours. It is for your safety, as well as his."
"He wanted to wait with me," Amanda said, tucking her arms a little more tightly around Spock, and looking down at his ears, which had come out of her as round as a human baby's, but had developed the elongated pinnae in a day. That was a characteristic particular to Vulcan babies.
Spock had also put on weight in the way of Vulcan children, too, so he was sturdy and solidly-built. At two and a half years old, with the heavy gravity of Vulcan, he was beginning to be a little awkward for Amanda to hold, and she struggled a little when standing up from the bunch.
"Would you like me to -- "
At Amanda's expression, Sarek stopped before the next word, and he let her wrestle Spock onto her shoulder. He put his hand in the small of her back, and they walked into the main part of the house together.
6.
"Mother, have I not performed a sit-up correctly? I do not understand your amusement. If there are any technical flaws, I ask that you direct my attention them now, as the physical trials for Starfleet are in three months, and I do not wish to be fo -- why are you laughing at me, Mother?"
7.
In all the years that Spock is first a student, then an instructor, at Starfleet Academy, his father never comes to see him. In fact, for a number of years, Sarek refuses to even speak to him on calls.
8.
Entirely closer to the time when the Enterprise would be setting off on her first true voyage under Jim than prudent, Spock cashes in the transportation chits that he has collected over all his years of service with Starfleet. He could have taken a shuttlecraft from the Enterprise, and there was, indeed, one that would have benefited from an extended trial run, but it would have been somehow inappropriate. Instead, Spock takes the common transport cross-continent, then walks the last mile, then takes the old-fashioned stairs to the fifth floor. Stairs had been common on Vulcan in meditative towers, and Spock finds himself in a meditative mood when the door opens.
"I'm afraid she's asleep," the girl says. "And she sleeps so little these days -- the medication makes her too tired. Can you wait?"
"I apologize, but my time is limited. The Enterprise is due for Alpha Centauri in a few hours."
She shows Spock into the bedroom anyways, and he looks at the thin body lying under the covers, waiting to die. The woman does not quite recognize her daughter; Spock states his name and relationship, but he does not think that she understands. When leaving, though, she grips his hand, and he receives a sudden, overwhelming memory of yellow sunshine, the smell of long Earth grass in the summer, and the strength of being young.
The girl who answered the door is adopted. Spock is half-Vulcan. Afterwards, the two of them sit together in the kitchen, eating pound cake and listening to the wind rattle against the window and make the windchimes bang against each other.