"The current POSIX standard defines source code-level compatibility for only two programming languages: The C language (C99) and the command language (shell)."
There used to be POSIX.5 which standardised Ada bindings and POSIX.9 which standardised Fortran bindings, but both were abandoned (I assume due to lack of interest)
There is an argument that Awk's language isn't the same category as it is a DSL not intended to be a general purpose language (it is turning-complete, but was not specifically designed as such), and awk itself is considered a complex tool not a language interpreter.
Though having said that, any definition that separates awk from general programming languages like that could probably apply to shell syntax too.
and m4 https://pubs.opengroup.org/onlinepubs/9699919799/utilities/m...
and ex https://pubs.opengroup.org/onlinepubs/9699919799/utilities/e...
and bc https://pubs.opengroup.org/onlinepubs/9699919799/utilities/b...
unix isn’t short of programming languages!