In this study we defined a methodology for examining the combined effect of F0 and duration in accenting a syllable, leading to the perception of narrow focus in a short sentence. The F0 and duration variables were manipulated independently in one word in each of three four-word sentences. F0 was manipulated through use of the Fujisaki model of intonation, whereas duration was manipulated using Praat software. Subjects were asked indirectly to determine whether any word was accented. Initial results showed that perception was influenced by changes in F0 more than by changes in duration, with some degree of interplay between the two variables. Identification curves show a categorical perception of accent as a function of F0.