I would say any JSON or YAML that carries semantics with the syntax is a language. It may be a configuration language rather than a programming language, but it’s a language rather than just generic data for some program to slurp.
> any JSON or YAML that carries semantics with the syntax is a language
semantics are defined by the converter/compiler/interpreter, and that is the process which is going to consume the said json/yaml. if the json/yaml is going to be consumed by any process then the semantics are inherently defined, so by your definition all jsons/yamls are in their own a "language" (or they are not being consumed at all), which just defeats the purpose of calling it a language at that point.
> any JSON or YAML that carries semantics with the syntax is a language
semantics are defined by the converter/compiler/interpreter, and that is the process which is going to consume the said json/yaml. if the json/yaml is going to be consumed by any process then the semantics are inherently defined, so by your definition all jsons/yamls are in their own a "language" (or they are not being consumed at all), which just defeats the purpose of calling it a language at that point.