Why are Interpreted Languages Slow?

Question

I was reading about the pros and cons of interpreted languages, and one of the most common cons is the slowness, but why are programs in interpreted languages slow?

Answer 1

Very few contemporary scripting languages are "interpreted" these days; they're typically compiled on the fly, either into machine code or into some intermediate bytecode language, which is (more efficiently) executed in a virtual machine.

Having said that, they're slower because your cpu is executing many more instructions per "line of code", since many of the instructions are spent understanding the code rather than doing whatever the semantics of the line suggest!