Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has received more attention in recent years as a treatment option for regulating the symptoms of Parkinson's disease. Previous studies of DBS documented consistent improvements in motor function but more variability in speech outcomes. In the present study, six participants diagnosed with idiopathic Parkinson's disease who reported worsened speech with stimulation were recorded performing speech acoustic tasks with the stimulators on, and again with the stimulators off. Improvements were noted for most participants in measurements of formant slopes, long term average spectrum (LTAS) of a sustained vowel, and spirantization with stimulation on. Stimulation negatively affected most participants' vowel space area, verbal fluency, sequential motion rate, and LTAS while reading and describing a picture. Measures of stop gap duration, alternating motion rate, and voice onset time were within normal limits for most participants across both stimulation conditions.