Our friends at Tin House have it exactly right.
Jill: How did you decide to make Quinn and her sister synesthetic? Are you?
Zumas: I’m not. Well, I didn’t think that I was at all, but I discovered as I started researching synesthesia that I could maybe be said to have a very mild form of it. Ever since I learned numbers and letters I experience them as having genders. It’s the same with months of the year and days of the week. The way they’re organized in my mind is coded by gender. Which, again, is not exactly synesthetic, because it’s not two different sensory perceptions. But it is a way of organizing information that feels inherent to the thing. It’s not like, “Oh, I decided to make Tuesday a girl.” I always just believed that that’s what it was, and it couldn’t be separated.
But most synesthetic people have a more pronounced mixing or a collapsing of the wall between color and sound or smell and sight. It’s something I’m interested in as it surfaces in language, how we have a lot of ways of describing one sensation. We can only describe it with another sensory vein, such as smell. Most of our words for smell are actually related to the four other senses, because it’s so hard to explain to someone what something smells like. We say something smells sharp or bitter or loud.
There was that interest, but I wanted the sisters, the remaining one and the lost one, to have shared this bond, this special way of being in the world. And synesthesia does run in families — their father has it and they have it, but the mother and brother don’t have it.
It became another signal of or marker of Quinn’s apartness, her difficulty in being in the world.
—From the Powells.com interview with Leni Zumas, author of The Listeners