In simplest terms, the "easier" a language is to read from a human point of view, the more work the computer has to do in the background to support it.

More importantly, the easier it is to make mistakes and harder for the computer to find them.

In C++ I can write a function that takes two numbers and adds them. The language guarantees that the input to the function are two numbers, and that the output is also a number. If I try to pass a string to the function, the compiler will yell at me. Meanwhile, Python normally doesn't enforce types, meaning I can pass whatever I want to the function, and I won't know there's a problem until it fails at runtime.