Yes. Select part 1, press the [MODEL BANK] button to make it light, then press MODEL button [15], and you can use knob [1] to select a vocoder sound (two types with the factory settings).
In order to use the vocoder, connect a dynamic mic or an electret condenser mic to the rear panel MIC IN jack, and adjust the MIC GAIN appropriately. When you input sound from the mic while you play the keyboard, the effect is applied.