Firstly there was no such thing as 'Roman' a language, they spoke Latin and 10 in Latin is 'decem'.
ten
The Roman numeral for ten is X
Ten = V
The Roman Numeral system is considered a base ten system.
X
The root of the word December is Decem, which is the latin for the word ten. Interestingly this means the word December means tenth month, not twelfth month as is the words common usage today.
X in Roman Numerals = TEN
The Ten Tables where the first written Roman law code. They were compiled in 451 Bc and 450 BC.
Ikumi is the Kikuyu word for the English word ten.
romanImproved answer:X = 10
Ten
It is used by Romans, because they use Roman numerals. In Roman Numerals, x represents ten (10)