This study aimed to investigate the differences in colour naming between the English (British) and Mandarin (Taiwanese) languages. A constrained method,vas employed, with 20 British and 20 Chinese adults. All the experiments were conducted under an artificial daylight, using 1526 colours from the Natural Color System (NCS). Each subject was asked to find the colour(s) corresponding to basic names, modifiers, and secondary names in terms of one colour (focal colour) or a colour region (colour volume). Little difference in chromaticness and hue,was found between the two languages, but a systematic discrepancy was found in blackness. Because this could have been caused by different surrounds, i.e., gray, and white walls used for the British and Chinese experiments, respectively, a verification experiment was carried out using a panel of ten Taiwanese subjects against a gray surround. The results proved that the lightness difference found earlier was indeed caused by the surround.