Business language is directed both outward, toward the general public and inward, toward the particular type of business. In the first instance, it approximates lay language and has contributed some expressions to common usage. In the second instance, it departs from lay language and becomes specialized within each industry, sometimes to the point of mutual unintelligibility. However, this distinction is largely lexical and not grammatical, and is largely written and less commonly found in spoken forms. Common business language is found within the area of conventionalized transactions governed by the courtesies and formalities of business life, which are almost universal. The choice of appropriate form is determined by subject matter, the occasion, and shared knowledge and social relations of the communicators, and is heavily dependent on an internal knowledge of the business. Spoken and written communications are very different in business, and each deserves separate treatment in instruction. Those involved in teaching business English should consider building and analyzing a corpus of oral business language. (MSE)