||This category covers discussion of a wide range of issues, including the following. 1. Linguistic Convention. What is the nature of the relation between individuals and the languages that they can speak? In particular, should it be accounted for by appeal to convention and, if so, what account should be given of the nature of convention? 2. Idiolects. What determines the properties of individual speakers' languages? Are those properties determined by properties of the individual speaker, or might properties of other speakers, or communities of speakers (perhaps including past speakers), figure here? Are there shared or communal languages? What is the relation between individuals' languages and shared or communal languages? 3. Knowledge of Language. Do speakers of a language know that language? If they do, in what does their knowledge consist? Is it a form of propositional knowledge, a form of practical knowledge, or some other form of knowledge? And what is it that they know when they know a language? 4. Linguistic Universals. Are there properties shared by all possible languages? Are there properties shared by all natural, or humanly acquirable, languages? If there are such properties, what are they? And can we explain why there are precisely those universal properties? 5. Private Language. Is it possible for there to be a language that, as a matter of necessity, only one person speaks? Or are there arguments that no such language is possible? 6. Words. Are there such things as words? If there are, what is their nature? Are words concrete individuals or types, or do they belong to a different metaphysical category? What are the principles that govern how words are to be counted?