Linguistic sign should be considered as “signifier” with material shell, rather than a purely psychological entity combined with “signifier” and “signified”. “Signified” can be psychological ideas or feeling, or objective things. Meaning is something external, not intrinsic, to linguistic sign. The connection between meaning and linguistic sign is based on repeated conditioned reflex. Linguistic sign is the “sound” with material shell, serving as the carrier of “meaning”. The original connection between “sound” and “meaning” can not at all be arbitrary, but it was iconic. This iconicity shows great contingency among different languages. As this iconicity dies out, the contingency is exaggerated as arbitrariness.