Programming languages are notation.
A programming language cannot be "fast" or "slow".*
It's a LANGUAGE. It's how you communicate by laying down, in writing, the way that a program treats and defines its inputs and outputs.
* wrt how a program encoded in that language runs, that is—it is certainly the case that some forms of notation are faster/slower to write than others
You can talk about a certain software package's performance—
"The interpreter distributed with software Z is very efficient."
"The code generator from the Y toolchain outputs binaries that execute speedily (on the subset of hardware that we're interested in)"
But these are properties *of _THAT_ software package*, not a property of the notation that a given program is expressed with.
Colby Russell