Our project investigates the meaning of and, or and their counterparts in other languages. These two classes of expressions (henceforth referred to as and and or) seem to have a central status in natural language grammars. Almost all languages express at least one of them, and in many languages, they can be used to combine expressions of almost all grammatical categories.

For this reason, linguists are interested in developing unified theories of their meaning that let them combine with expressions of any kind. There are two conflicting research traditions in this field. One of them assigns a so-called Boolean meaning to and. Informally speaking, the meaning of any expression involving and is reduced to the meaning of an expression in which and combines with full sentences. For instance, (1-a), in which andcombines with two verbs, is reduced to (1-b).

(1)

1. Jane drinks and smokes.
2. Jane drinks and Jane smokes.

However, there are examples which cannot straightforwardly be reduced to conjunctions of sentences. For instance, (2-b) sounds odd and cannot express the meaning of (2-a). For this reason, many linguists assume an additional, non-Boolean meaning for and.

(2)

1. Jane and Mary met in the bar.
2. Jane met in the bar and Mary met in the bar.

If and had two unrelated meanings, one would expect that some languages systematically use different expressions for Boolean and non-Boolean and. We suspect that this is not the case and conclude that one of the two meanings should be reduced to the other. For theory-internal reasons, we think that the non-Boolean meaning is probably the basic one. However, these hypotheses cannot be tested on the basis of the data currently available. Detailed studies of the meaning of and only exist for a small number of languages.

Therefore, our main goal is to collect the necessary data to examine the predictions of our hypotheses. This will be done using SSWL, an online platform which allows linguists to contact informants for a wide range of languages and ask them questions about their language. The informants enter their answers into a freely searchable database. In addition to collecting data on the grammar and meaning of and in various languages, we aim to improve the existing theories of non-Boolean and. If our non-Boolean approach to and holds up, it also raises interesting problems for some current theories of the meaning of or, which suggests that these theories need to be revised.