We gave Anna a pair of twin baby dolls for Christmas. One is dressed in pink, and the other one in yellow.
Anna calls them Baby Purple and Baby Green.
Although she has words for other colours, she seems to regards purple and green as the primary colours, so the other colours are most frequently mapped to the two basic terms.
This seems to contradict Berlin and Kay’s 1969 study that concluded that the most basic colour terms were black, white and red, followed by yellow and green (in no particular order), followed by blue, then brown, and finally other colours such as purple.
Of course, their study was about languages spoken by adults, so perhaps very different rules apply to child language development.