We have recently developed a statistical model of speech that focuses statistical modeling power on phonetic transitions. These are the perceptually-dominant and information-rich portions of the speech signal, which may also be the parts of the speech signal with a better chance to withstand adverse acoustical conditions. We describe here some of the concepts, along with some preliminary experiments on digit recognition. These experiments show that the new models, when used in combination with our more standard models, can significantly improve performance in the presence of noise.