Measurements of formant frequencies throughout the vocalic portions of a number of phonemically symmetric consonant‐vowel‐consonant utterances have been performed using spectrum‐matching techniques implemented on a digital computer. The contours representing the first two formants as a function of time are described in terms of several parameters, including initial and final frequencies, midpoint frequencies, durations, and measures of curvature. The data illustrate the manner in which each of these parameters is influenced by the features of the vowel and by place of articulation of the adjacent consonants. The results provide evidence that diffuse tense vowels in English are characterized by diphthongal asymmetric articulatory motions, whereas nondiffuse vowels are not, and that the influence of the consonantal environment on the articulation of the vowel is greater for lax vowels than for tense vowels. Some general statements are made concerning the extent to which contiguous vowels and consonants influence each other's production.