This story is set on Japan. I also used the last name first basis. If you're quite familiar with manga and anime, feel free to skip this. If not, here are the words used throughout the story:
Aniki: older brother
Chan: honorifics used usually for girls, babies, younger children, or those older than the speaker
Fusuma: bamboo framed panels made of thick opaque paper that is used as partition between rooms or doors for closet
Gakuran: school uniforms for middle school and high school boys. The second button from the top is commonly given to someone he likes or asked by someone who likes him in a way of confession.
Half: (Hafu) refers to somebody who is biracial
Hanten: short winter coat padded with cotton
Izakaya: a pub or drinking establishment that also serves food
Kimono: traditional long, wide sleeved robe tied with a sash called obi
Koshien: a baseball stadium in Hyogo Prefecture where the annual high school baseball tournament is held
Kun: honorifics usually used for male of the same age
Obi: kimono and yukata belt
Ojii-san: grandfather
Oji-san: uncle but can be used to describe middle aged men
Okaa-san: mother
Onee(san): older sister
Otou-san: father
Sake: Japanese fermented rice wine pronounced as SAH-kee
Sama: the more respectful suffix than san used for people of higher rank than oneself
San: the most common honorific used to address someone between equals of any age.
Seiza: a traditional formal way of sitting with upright kneeling position
Senpai: senior/upperclassman in school, club, or circle
Sensei: teacher but can also be used for doctor, writer, politicians
Shoji: latticed bamboo panels covered with translucent rice paper that can be used as door, window, or partition
Tatami: traditional flooring made of woven straw. Its sizes differ in each region and usually used to determine a size of the room
Wagashi: traditional confections that are usually served with tea
Yukata: light cotton kimono worn in summer festivals and after bathing in traditional inn and hot spring
Zaisu: chair with no logs but normal chair back