Language seems to be important in White Teeth. Throughout Zadie Smith's story, you could argue that many of the characters’ main struggles connect to their relationship to language.
For instance, you might think about how important language is for Samad. For him, it’s as if language is a way to solve the problem of his tumultuous, conflicted identity. Early on in the novel, Samad “desperately” wishes he could hang a placard around his neck that clearly articulates his pained situation. Since such a placard doesn’t exist, Samad cultivates the “urge, the need, to speak to every man” and explain himself. For Samad, language isn’t just important: it’s something like an obsession.
You could also argue that Millat’s fundamental relationship is with language. He seems divided between the secular, liberal language of the West and the disciplined, dogmatic language of KEVIN. The language of the latter is important since it leads to violence.
Magid, too, seems to have an important relationship to language. Like his brother, Magid seems to be drawn to language that is clear and concrete. However, Magid doesn’t find this stable language in religion: he discovers it in science.
Overall, it seems safe to argue that language is important in White Teeth because its abstract, subjective quality creates a constant tension with the clarity and objectivity that many of the characters hope to achieve.