A model for the generation of fundamental frequency contours (F₀ contours) of spoken, sentences is presented for the purpose of elucidating the relationship between the sentence F₀ contour and the linguistic and non-linguistic information. It is based on a quantitative formulation of the process whereby the logarithmic fundamental frequency is controlled in proportion to the sum of two components corresponding respectively to the effects of phrase and accent. The model's parameters were determined to give the best approximation to an observed F₀ contour on the basis of the mean squared error. Analysis of natural utterances of various declarative sentences of Japanese revealedthat the model can generate close approximations to observed F₀ contours from a set of discrete commands and a small number of parameters. The extracted parameters were found to be closely related to linguistic factors and factors constituting thenaturalness of speech. These results provide a means for generating natural F₀ contours from a small set of parameters and rules for synthesis.