Ever since immemorial times, when man hardly realized his role in the heart of nature, the sounds were not enough to understand his fellow-creatures.
Humans may have communicated in a form of protowriting through markings alongside paintings of objects or beings around him and more than that, though the markings seem too simple to represent full language, in some cases, could have been used to convey geographic information or to aid in remembering the parts of ceremonies. Perhaps even since then the man realized that the symbol might overrule the time barrier, resisting as a trace.
Over time, some signs have acquired sacred value. What man could not verbalize was represented graphically, symbolically, so new terms were born, and thus the spiritual dimension was shaped.