This book is a critical reflection on the "linguistic ideologies" which support most scientific approaches to the study of human language in Western history. Starting from HumboldtÆs revolution in language theory, it tries to build a bridge between the European tradition of critical philosophy and the theoretical framework of the constitution of research objects and methods in modern linguistics. The factuality, individuality, and historicity of human language are here the main pillars of a reflection that takes into account the broad indeterminacy of factual linguistic meanings, both in ordinary speaking and in professional "speaking about speaking". Humanism as the ethic framework of human sciences, dialectic logic and epistemology, recent developments of neural sciences, and aesthetics as a means of recovering the materiality of linguistic behaviour, are the main conceptual tools used by the autor.