Many languages still bear the traces of a quinary system, and it is reasonable to believe that some decimal systems passed through the quinary stage. These two other systems are the quinary, base 5, and the vigesimal, base 20. It is true that in addition to the decimal system, two other bases are reasonably widespread, but their character confirms to a remarkable degree the anthropomorphic nature of our counting scheme. That answers your question, but note that there are traces of other bases in our number words: (English, German and Norwegian all belong to the Germanic subfamily of Indo-European French belongs to Italic.) Note that we can still discern a trace of "two" in "twelve". There are apparent exceptions, such as the English eleven and twelve, or the German elf and zwölf, but these have been traced to ein-lif and zwo-lif lif being old German for ten.Īnd presumably this was inherited in other Germanic languages. All these languages have independent words for 1, and some languages for even higher decimal units. In all Indo-European languages, as well as Semitic, Mongolian, and most primitive languages, the base of numeration is ten, i.e., there are independent number words up to ten, beyond which some compounding principle is used until 100 is reached.
Indeed, there is no mistaking the influence of our ten fingers on the “selection” of the base of our number system. Let me quote from the classic book Number: The Language of Science by Tobias Dantzig (1930, republished with nice foreword by Barry Mazur): Actually, eleven and twelve also seem to be derived from 10+1 and 10+2.