Your question is obviously true since there are current people who don't use the decimal system. Famously the Danish don't exactly use a decimal system all of the time. Even modern society doesn't, for time which is base 60, which the sumerians used. There are also several people in Papua New Guinea that do not use decimal. Ndom people for instance use base 18.

This would technically be a linguistics question, and /r/linguistics may have more information for you.