This study intends to identify acoustic and phonetic characteristics of the speech of Parkinson's Disease (PD) patients, usually manifesting hypokinetic dysarthria. A speech database has been collected from a control group and from a group of patients with similar PD severity, but with different degrees of hypokinetic dysarthria. First and second formant frequencies of vowels in continuous speech were analyzed. Several classifiers were built using phonetic features and a range of acoustic features based on cepstral coefficients with the objective of identifying hypokinetic dysarthria. Results show a centralization of vowel formant frequencies for PD speech, as expected. However, some of the features highlighted in literature for discriminating PD speech were not always found to be statistically significant. The automatic classification tasks to identify the most problematic speakers resulted in high precision and sensitivity by using two formant metrics simultaneously and in even higher performance by using acoustic dynamic parameters.