The term machine language technically is machine executable code. Assembler is sometimes erroneously called machine language. Machine language is binary.
Mnemonics are used in assembly language in place of op(eration) codes.
ASCII (American Standard Code for Information Interchange) is an encoding system for characters.
Boolean is a false/not false data type, which in C is implemented as an integer. Zero is logical false, anything else is not false (logical true).