It was almost 200 years ago that Wilhelm von Humboldt developed his ideas about what language is and does; since then, the dominant linguistic movements of the Anglophone world have given little consideration to his writings. Even though his work is often referred to on a superficial level, the reception of his writings in the Anglophone world is at best partial and certainly problematic. There is, however, good reason to believe that his time is yet to come. The present Special Issue wishes to point in this direction and demonstrate the significance, and timeliness, of his thinking. Thinking language: this expression is obviously not very idiomatic in English. It is coined in analogy with the German Sprachdenken or the French pensée du langage. ‘Thinking’, here, is distinct from either ‘theory’ or ‘philosophy’. When speaking or thinking about language one cannot look at the object of analysis from the outside, and since theory – derived from the Greek theoria, which meant ‘looking at’ – entails an external perspective, a view on something, there cannot really be a theory of language at all. There is no outside view on language; the object and the vehicle of thought are in the case of language the same. And with Humboldt, language is even the constitutive and generating force of the entire process. The phrase ‘philosophy of language’ is no less misleading, particularly in the Anglophone world where one would immediately think of analytic philosophy, which historically has represented a very different approach to language. Even after Frege and Wittgenstein made the history of philosophy aware of its linguistic constitution, there remains a tendency to see language as an obstacle to ‘clear’ thinking, and to consider any constitutive aspect of language to thinking as regrettable, something to be overcome rather than thought. Thinking language, by contrast, does not strive for the one correct neutral and objective language since it does not believe in its possibility or even its desirability. Rather, thinking language is convinced that it is precisely the diversity, the multitude of perspectives – given through different languages, but also within every language and in every single speaker and even in every moment of speaking – which endows the human world with its richness. This tradition, for which Humboldt remains the most important thinker, has at its inception Leibniz’s description of language as demonstrating ‘the wonderful variety of the operations of the human mind’.1 Language’s purported lack of clarity, of the one truth, which for others supposedly exists independently of our means of expression, becomes here a cause for celebration, the precondition for newness coming into the world.