Partially Japanese, Sensory, Precise
We say partially Japanese because there isn't a lot of actual Japanese spoken in this novel. But if you pay close attention, Kogawa writes the dialogue of the Japanese speaking characters as if they're speaking Japanese in English.
It might seem bizarre at first, but Kogawa is attempting to give English-speaking readers the experience of hearing Japanese. For example, this is how Naomi's mom speaks:
"It was not good, was it?" Mother says. "Yoku nakatta ne." Three words. Good, negation of good in the past tense, agreement with statement. It is not a language that promotes hysteria. (11.20)
In English, Naomi's mother would be more likely to say, "You didn't do a good thing," or "The hen was bad." Japanese allows Naomi's mom not to blame anyone, but it can also be so vague that it causes confusion.
So Kogawa replicates that ambiguity in her Japanese/English dialogue. It's not quite normal English… but it's not quite Japanese either.
This lady sure knows how to engage all of your senses. Some novels only focus on a few sentences, like sight. But Kogawa uses all of the senses in a way that the reader is able to experience sensations right along with the characters. This is how Naomi feels when she learns about Uncle's death:
There is an odd sensation like an electrical jolt but not so sharp—a dull twitch simultaneously in the back of my head and in my abdomen. And then a rapid calming. (2.57)
You can understand how she feels, right? Or maybe your stomach even got a little upset too? That's a master of sensory prose at work.
So much of this novel is about language and its power that it makes perfect sense for Kogawa's style to be very precise. There are many scenes that may not reveal their true meanings until after the book is over because she is so careful with her vocabulary. This is not a book for a lazy reader.
This precision spills over into the characters' experiences. For example, it is not enough that Naomi dreams of her mother and Obasan's love. She dreams of a very specific Japanese word for love. She says:
Once I came across two ideographs for the word "love". The first contained the root words "heart" and "hand" and "action"—love as hands and heart in action together. The other ideograph, for "passionate love", was formed of "heart", "to tell", and "a long thread". (35.6)
There is a pretty big distinction between the two words, and Kogawa tries to make that clear to her non-Japanese readers. That's a lot of work. Other writers might just have written "love" and hoped for the best.