Identification of speakers' voices in open trials of corruption cases: acoustic phonetic analysis Tengku Silvana Sinar 1 , Nurlela 2 , T. Thyrhaya Zein 3 {tengkusilvana@usu.ac.id 1 , nurlelamajrul@usu.ac.id 2 , t.thyrhaya@usu.ac.id 3 } Universitas Sumatera Utara, Medan, Indonesia Abstract. This study is about the identification of speakers' voices on a recording of forensic corruption open trials case for defendants held at the Medan District Court. The purpose of the study is to find out the functional features of duration, intensity, pitch, and frequency of the speakers' voices. The use of qualitative research methods was applied and Praat software was used for collecting and processing the data of speech sounds. The results of the study showed that the level of differentiation in voices delivered by judges, prosecutor, and witnesses, and the functional features of duration, intensity, pitch, and frequency of the speakers' voices in oral language used in trial corruption cases vary to one the other. Keywords: Acoustic phonetics, corruption case, forensic linguistic, praat 1 Introduction Circular Number: 04 of 2012 from the Supreme Court, with Number: 08 / BUA.6 / HS / SP / VIII / 2012 is concerned with recording of proceedings stating that the trial at the court of first instance must be accompanied by audiovisual [1]. Following the relevant statement of Circular Number from the Supreme Court and as stated in CHAPTER II item 6 through 15 presented previously, (furthermore read Law Number 30 of 2002 [2]) about a large duty, authority and obligation of KPK (Corruption Eradication Commission) to the state, its role in combating corruption never stops from time to time especially as big and wide country like Indonesia (coverage from the island of Sabang to Merauke) they commit that Indonesia must be free from corruptors. Therefore, the participation of the whole society and academicians in state and private universities is needed to solve the problem of the trial of corruption cases both in the forms of teaching and research in accordance with the dedication to the nation. This research was conducted to explore the lingual data used by people suspected of gratification at the trial, specifically, the objective of this research is to identify the indication and symptoms in the use of corrupt languages in terms of frequency, duration and intensity of voices. Since the aspects in question are functionally interrelated with the approach used in this study, therefore forensic linguistics in a trial of a corruption case was combined with the experimental approach to measure the prosodic characteristic of sounds. The experimental approach was applied to detect and identify the acoustic of the voice symptoms with Praat software program. Experimental approach is a phonetic study using an accurate measuring device ([3], [4]) either in tracing the pitch movement or measuring the acoustic characteristics. ICO-ASCNITY 2019, November 01-03, Padang, Indonesia Copyright © 2020 EAI DOI 10.4108/eai.1-11-2019.2293992