Look at something like java. Java has a core set of design elements. It was built by a person with some philosophical leanings("Everything is a class", "Checked/Unchecked exceptions being different things", "no first class functions") Then it has standard libraries(i/o, collections, threading/synchronization) each of these was built by a person with there own set of biases and understandings. The original Collections implementation has lots of mutable data structures then later Josh Bloch decided that he didn't like that anymore and stopped adopting "immutability" as core design philosophy. Immutability was not previously considered important when evaluating a java implementation. What you end up with is a mish mash of different opinions that only gets more different as you go.
Some 3rd party libraries like Guava didn't jibe with the Philosophical leanings of the language itself and looked for work arounds. They went as far as to create their own implementation of functions as a first class citizen in a language that was expressly designed to omit them. Some commonly used Android libraries do this as well.
My point here is that "language" can mean lots of things. It can refer to the language itself, its run time, the syntax+runtime+community. What is idiomatic and on, on, on. People and groups of people have the philosophies. I'd like to see the author point to something a little more critical about the differences between these two concepts. This premise is a little muddled.