2000 years ago, the modern numeral system was invented in India.

Ten glyphs to represent the digits 0-9 were used.

The same system was then adopted in Arabia and later Europe.

When the ‘systems’ are different, glyphs can’t be mapped 1→1

Take the word “Zen” for example, when it spread from India to Japan.

The pronunciations changed a lot between languages, and the written systems adapted to these languages. Sounds and other features that exist in one language do not in some others.

So, the corresponding letters of these words in different languages are not the same.