How were the first languages created

Question

It still baffles me how so many years ago someone was able to create a computer language that could be understood by a machine even if it was primitive but the my main problem is how did she design the syntax and the error codes if there were any at all

Answer 1

As far as I understood once, the first executable program was created directly of zeros and ones, and then it was extended to be self-compiling, so they had an application that could be used to compile new pieces of code.