Examining Computer-Generated Aeronautical English Accent Testing and Training

Abstract

Objective: This thesis focused on the persisting problem of language-related issues, in pilot-air traffic controller (ATC) communication, particularly in relation to foreign accents interfering with pilots’ understanding. It examined the effect of foreign accents embedded in human and computer voice (HV, CV), as well as demographic background on the level of understanding of the participants.

Background: Studies focusing on the impacts of foreign accents in Aviation English (AE) are scant. Accents have been identified as one of the main contributors to miscommunication between pilot-ATC radiotelephony communication in the air, thereby endangering flight safety. It is necessary to examine how to train ab initio and returning pilots on extracting accurate meanings from an accented instruction coming from ATCs. This thesis introduces a Text-to-Speech (TTS) supported by artificial intelligence for such training.

Method: Multiple studies (a total of six) were conducted: 2 literature reviews, 4 empirical studies. For the empirical studies, 50 participants from the University of Waterloo who had experiences with flight or had experience in listening to pilot-ATC communications were recruited. They were put into two Voice Groups (HV and CV) one of which played only human voices and the other TTS. They completed two rounds (Round 1 and 2) of listening tests that contained both Aviation Script (AS; scripts read in foreign accents that were related to aviation context) and Neutral Scripts (NS; non-aviation scripts read in foreign accents with no contextual background). The foreign accents used in the listening tests along with native-accented English were three of the ICAO’s main languages: Arabic, Spanish, and French. Scores were analyzed according to the Script Types (NS, AS), Accents (Arabic, Spanish, French), Rounds (1 and 2), and Demographic Profiles (Age, Gender, Years of Speaking English, Flight Hours, Flight Ratings, Language Background, Familiarity with Arabic, Spanish, French, and Aviation English).

Results: For the empirical studies, in the HV group, participants improved their scores from round 1 to 2 in the AS portion of the tests. In the CV group, participants improved their scores in NS. Examination of demographic information showed that non-native English speakers (NNES) tended to perform more poorly on average than native English speakers (NES). Being familiar with Aviation English was beneficial for completing listening tests. Also, having a higher flight rating was beneficial. Having more years of speaking English was only partially advantageous. Post survey results were analyzed, and it was found that participants in the CV group found the speech mostly unnatural. Those in the HV group also expressed difficulty in understanding due to accents but mentioned that the speech was clear, and scripts were representative of real-life pilot-ATC communication. Participants expressed foreign accents interfered with their process of logical deduction when choosing answers on the tests. Participants – regardless of whether they belonged to the HV or CV group – found NS difficult and challenging due to lacking contexts when answering questions on the tests. For AS, participants were able to piece together information using contextual knowledge related to aviation.

Conclusion: Accents do interfere with pilots’ understanding in radiotelephony communication by making extracting content challenging, which in turn makes interpreting messages or instruction difficult. This is an important finding as it will affect situational awareness to a certain extent when making decisions on the fly. Pilots have to multi-task whenever possible to keep the passengers safe and to find the best route to get to a destination that maximizes fuel efficiency but minimizes passenger wait times. Communication plays a large role in deciding the fate of an aircraft’s journey. In this logic, accents can be said to be at the core of this overarching issue with language in the context of aviation. Therefore, training with a new technology such as TTS, along with other educational resources, could confer a valuable experience and exposure to pilots who are either beginning or re-starting their language training.