“Every language is different AND [e]very language is the same.” Paradoxes like this one, where everything is somehow different and still the same, are commonplace in anthropology and other areas where one deals with the importance of the relative and the universal aspects of a certain topic. In the field of linguistics, the case for a strong variation between languages leading to a one’s unique habits of speech at the extreme, is as valid as the case that on some level, like Noam Chomsky suggests, all languages have universal aspects.
Between the extremes of unique idiolects and commonly shared linguistic universals there is a large middle ground. Taken all together, one might be able to draw a complete hierarchy of resemblances of conceptual systems that could form an arch connecting both extremes – the unique and the universal levels – as can also be seen in the graphic below:
Starting on the left side with the idiolect, which is unique to a single individual only, one could go on to the speaking habits common to a family and continue to shared features in the previously-mentioned social dialects of an economic class, which are in many ways on par with regional dialects and specific versions of a language commonly bound to a certain area in terms of variation. Only then can one speak of common features of a standard language, such as English or German, and then go on to what a standard language has in common with other standard languages, similar or distantly related. Finally, one would reach the language universals, which are found in all languages, on the right-hand side of the arch.
 ISAC, Daniela; REISS, Charles: I-Language. An Introduction to Linguistics as a Cognitive Science. 2nd Edition. Oxford: Oxford University Press 2013, p. 16.
The Arch from Linguistic Universals to the Idiolect is also part of my pre-academic paper “Thinking in and beyond Language: On Linguistic Relativity and a Model of Conceptual Thought”, which can be found here.