"The classification of things is not always straightforward and can often be mainly dependent on culture," said Horst Simon, a professor of historical linguistics at Freie Universität Berlin and initiator of the conference. Because sparrows are birds. So are eagles and penguins. Whales and bats are mammals. And in China tomatoes are served on a plate of fruit for dessert along with melons and peaches. These categorical difficulties also exist in the field of language. "Even though the average classroom might suggest otherwise, upon closer examination there are many grammatical phenomena that do not fit well in the categories, and sometimes not at all," said Horst Simon. This raises fundamental issues with regard to the sense and nonsense of established grammatical categories. The search for answers is not only of theoretical academic interest, but also important for many applications, for example, for automatic language analysis in modern computer applications, or in the organization of textbooks for teaching foreign languages.

Other important questions that the conference participants will deal with include, for example: Is the German word "bausparen" a verb or a noun? Does the sentence "Peter will be in the kitchen." refer to the future or is it a conjecture? Or also: Does Old English have subjects? Are spoken and written language fundamentally different? And: when is a mistake no longer a mistake, but a rarely occurring exception?