This paper discusses the advantages and challenges of using speech recognition technology, on mobile devices, in order to improve usability of mobile learning applications in the field. Multimodal and voice technology that enables speech-based information retrieval and input, using mobile phones or handheld computing devices is explained. Use of multimodal technology helps to overcome the limitations imposed by the small screen of mobile devices and their cumbersome data input capabilities. This technology could be especially valuable in engineering and science education. During field trips, students involved in field monitoring, testing, or other activities using instruments or testing equipment, often need to enter and request information on mobile devices hands-free and eyes-free. The author describes a mobile prototype application of voice and multimodal technology, and discusses mobile usage scenarios that incorporate multimodal data communication during field trips.