Increasingly, speech input and/or speech output is being used in combination with other modalities for the representation and exchange of information with, or mediated by, computer systems. Therefore, a growing number of developers of systems and interfaces are faced with the question of whether or not to use speech input and/or speech output in multimodal combinations for the applications they are about to build. This paper presents first results on speech in multimodal systems from a test of a theory-based approach to speech functionality. The test used a large corpus of claims about speech functionality derived from the recent literature.