Fingers, and more fingers.

Is the thumb a finger?

In prehistoric times, two main dialects of Gilkesh evolved. One of the principal differences was the use of two different words for "finger": ishid, which included thumbs, and shus, which excluded thumbs. (Thumbs were called tus by these speakers.)

The development of numeration systems paralleled the naming of fingers. Tribes that used the thumb-inclusive ishid adopted the decimal system, while the tribes that called their fingers (but not their thumbs) shus used octal numbers. (As we've noted elsewhere, the octal system eventually prevailed, and evolved into the hexadecimal system used in modern times.) It's not clear whether the difference in numeration arose from the difference in nomenclature or vice versa, and it may be a chicken/egg question. But it is clear that some populations thought of all ten manual digits as the same entity, and named and counted them accordingly; while others, reckoning the thumb as a thing apart, counted only the fingers that shared a common name.

In Universal Standard Gilkesh, both terms are retained, with their original meanings, but the dialectal division has long since disappeared.