If people from different countries made up their own languages... why do some of them have the same alphabet?

Question

my mum asked me something crazy like... "how can i read Bulgarian numbers"... of course i just looked at her o.O... but (example)... french people speak french and British speak English.... but why do they use the same numbers and alphabet... like Chinese have weird shapes for letters... why do western European countries all use the same numbers and alphabet... (2893627452165Y/HDREAJHBVKGD) stuff like that... if they communicated about the alphabet why not just share the one language?

Answer 1

I guess the alphabet just spread by conquests of land and stuff but the language always prevailed :) And, lol, they're not weird shapes, they're characters

Answer 2

Languages are not "made up", apart from constructed languages. They evolved over thousands of years.