Based on experiments done with infants, this passage from the The Baby Lab suggests that language flows from pre-existing thought:
A few years ago, [Elizabeth] Spelke, working with Susan Hespos, of NorthwesternUniversity, fashioned a study around a curious linguistic distinction that is made by Korean but not by English. Korean speakers indicate whether an object fits loosely or tightly with something else--a ring on a finger, a shoe in a box, a cup inside another cup--whereas English speakers simply use "in" or "on." (In English, a wedding ring is "on" your finger, but it could also be "on" the kitchen counter.) Spelke and Hespos relied on looking-time measures to see if five-month-old infants living in English-speaking households would also note the loose-versus-tight distinction--by looking longer at a cylinder that fitted loosely into a container after they’d been habituated to looking at a cylinder that fitted tightly, and vice versa. The babies detected the difference. Apparently, before their own language had convinced them that the distinction wasn’t a vital one, they carried a concept of it in their minds. In 2004, Spelke and Hespos wrote up their findings in modest, technical language for the journal Nature. ("Our research focuses on the crosscutting conceptual distinctions between actions producing loose-and tight-fitting contact relationships ... ") As a result, the layman might not have noticed that they were making an aggressive philosophical claim: that thought preëxists language. "These findings suggest that humans possess a rich set of concepts before we learn language," Spelke told The Financial Times when the study came out. In the science press, her colleagues concurred. "How do we think about the world before we are corrupted by culture and the world?" the psychologist Paul Bloom asked. "One way to learn is to look at babies."
If you have some time, The Baby Lab is a terrific piece that looks at the career of Elizabeth Spelke, cognitive research on belief in very young children, her claim that there may be a biological basis for racism, and the differences - Spelke argues that the differences are small and dwarfed by the commonalities - between how women and men think.