This exercise synthesizes a vowel sound with a pitch frequency that linearly varies from a user-specified initial pitch frequency to a user-specified final pitch frequency. The formant bandwidths and center frequencies for each of 10 vowels are specified in the data file vowels_fmts_bw.mat along with the set of two-character ARPABet vowel names. Only three formant frequencies are specified for each vowel; it is assumed that the fourth resonance frequency is fixed at 4000 Hz for each vowel sound. The formant bandwidths for the first four formants are the same for each of the ten vowels and are set at the values 50, 80, 100, 150 Hz for the four bandwidths. The synthesized vowel is played out to verify the correct operation of the code. The file '5.11 Vowel synthesis.pdf' provides a User's Guide for this exercise.