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Accented Speech Understanding in Multinational Response Operations | Col. LaKeisha Henry (USA AF), DoD HCE | Dr. Douglas Brungart (USA Civ), NMASPC Walter Reed



Colonel LaKeisha Henry, MD, United States Air Force, is Division Chief, Department of Defense Hearing Center of Excellence (HCE), J9, Defense Health Agency, a collaborative effort with the Department of Veterans Affairs. Colonel Henry leads the HCE as it executes the congressionally-directed mission to optimize operational effectiveness, heighten medical readiness, and enhance quality of life for Service members and Veterans through collaborative leadership and advocacy for hearing and balanced health initiatives. Colonel Henry is an otolaryngologist within the San Antonio Military Health System and is actively involved as a teaching faculty member for the San Antonio Uniformed Services Health Education Consortium (SAUSHEC). She is an Advance Trauma Life Support Instructor and a Uniformed Services University of the Health Sciences (USUHS) Assistant Professor in the Department of Surgery. Colonel Henry earned a Bachelor of Science in Engineering Management from the United States Military Academy at West Point in 1992 and a Medical Doctorate from USUHS in 1998. She serves as the Chair of the Enterprise Registry Management Working Group for the Defense Health Agency and as a member of the National Institutes of Health/National Institute on Deafness and Other Communication Disorders (NIH/NIDCD) Advisory Council and as the Chair for a NATO Human Factors in Medicine communication-in-noise task group.


Douglas S. Brungart, PhD, is the Chief Scientist of the National Military Audiology and Speech Pathology Center at Walter Reed and is currently also serving as the Chief Scientist for the Department of Defense Hearing Center of Excellence. Dr. Brungart holds a BS in Computer Engineering from Wright State University (Dayton, Ohio), and an MS and PhD in Electrical Engineering and Computer Science from the Massachusetts Institute of Technology (Cambridge, MA). Dr. Brungart has authored and co-authored more than 40 peer-reviewed journal articles on auditory perception, and he has been issued ten US patents for hearing-related research.



Good communication is an extremely important prerequisite to success in NATO operations and exercises. However, operating in a multinational environment using a common language presents inherent challenges to communication due to the variety of accents, dialects, speaking styles, and English proficiencies encountered. This is particularly true when operating when there is background noise, over the radio, or when hearing loss is a factor.


Although multinational exercises are generally conducted in English, differences in accent among English speakers can make communication challenging. In some cases, differences in local dialect can cause difficulty even among native speakers of the English language. These problems can become more pronounced when non-native English speakers of varying levels of proficiency are involved in the conversation. The greatest challenges occur in noisy environments, when the listener has a hearing impairment, or when both factors are at play. In the study presented, participants in a multinational NATO exercise were asked to rate the difficulty of understanding native and non-native English speakers in different military environments. The results show that it tends to be much more difficult to understand non-native speech in noisy environments.



Human Factors in Medicine 285 Briefing given by Colonel LaKeisha R. Henry

Colonel LaKeisha R. Henry explained that military operations are chaotic and the ability to hear and communicate is critical to safety, command and control. Hearing is essential to military operations for communication, detection and identification, localization and acoustic stealth.

Hearing is vulnerable to damage from military noise exposures.
Up to 20% of active-duty Army soldiers have some degree of measurable hearing loss (HL). 6% have clinically significant HL.


The Department of Veterans Affairs Disability Awards reports that tinnitus and hearing loss have steadily increased amongst veterans since 1999.


Colonel Henry went on to explain that the Hearing Center of Excellence (HCE) was established by Congressional Mandate (Section 721 of Public Law 110-417 Duncan Hunter National Defense Authorization Act [NDAA] for Fiscal Year 2009).


This public law states that “The Secretary of Defense shall establish within the Department of Defense a center of excellence in the prevention, diagnosis, mitigation, treatment, and rehabilitation of hearing loss and auditory system injury to carry out the responsibilities specified in subsection (c).”


Collaboration, registration, facilitating research, development of best practices and clinical education are essential for the HCE.
The development of Human Factors in Medicine 285 led to a kick-off meeting in Paris in June, 2018. The subject of the meeting was understanding the spoken English of native and non-native speakers in NATO. The subject was also discussed in terms of listeners with and without hearing deficits.


In acoustic communication (speech and hearing) – among the most important abilities required by military personnel for the performance of their tasks – misunderstandings can cause fatal accidents or lead to errors in decision making, NATO coalition communication errors occur between native and non-native English speakers and listeners.
There are many communication considerations. English is used as the default language for NATO communication, many participants have a native tongue other than English, there is a heterogeneous extent of language training in the English language, and military vocabulary and tactical operational language and communication are not taught in school systems. Furthermore, dialects, pronunciation, slang, education and so on can make communicating in English more difficult. For example, in a typical NATO operation, a French soldier communicates with a German soldier and a Polish soldier in English. Pronunciation and understanding are reduced in comparison to a typical native English speaker. As already discussed, a hearing loss problem will further degrade the quality of communication.


Colonel Henry explained that different kinds of hearing tests are used in order to compare hearing capabilities of a “normal” population with those of soldiers who have hearing impairments and thereby assess hearing requirements and hearing ability in terms of a fitness for duty requirement.



Auditory Considerations for Command and Control in Multinational Environments presented by Dr. Douglas S. Brungart

Dr. Douglas S. Brungart and others were involved in an “evaluation of fitness for duty” test. The combination of the critical importance of hearing to military operations, the high level of noise in military environments and the prevalence of hearing loss in the military makes hearing one of the top readiness issues.


Tests were carried out using the Home Station Instrumentation Training System (HITS). Combat effectiveness was evaluated at different noise and hearing levels. Tests demonstrated a correlation between the degree of hearing loss and the composite score.


In another performance-in-noise test, the “impact of reduced speech intelligibility on reaction time in a naval combat environment” was tested.


This test showed that the acknowledgment rate suffered and situational awareness was affected as noise levels increased. A shift of attention away from critical visual information towards acoustical information may result in loss of situational awareness and missed information, especially when the operational tempo is increased. Furthermore, the workload shifts to others when team members are challenged. Repeat back requests increased, delaying other communication channels.
Additional investigation was carried out into situations in which the speaker or listener, or both, is a non-native speaker or are non-native speakers. A test was done with native and non-native speakers, revealing in a listening test that, while listening, non-native speakers need a 5dB higher signal to noise ratio. These tests also showed that non-native speakers experience a higher workload in noisy conditions than native speakers.


A survey conducted among 182 participants of the CPX and LIVEX at Trident Juncture 2018 identified that:
NATO operators experience difficulties understanding both native and non-native English speakers from other nations when compared to speakers from their own nation,
these difficulties increase in noisy environments or on the phone or radio, particularly when there are multiple speakers, or when the participant has a known hearing impairment, and communication difficulties sometimes lead to delays and errors in the mission.


Non-native speakers understand non-native speakers from their own country better if the level of English is low. The higher educated non-native speakers prefer native English speakers.


In a noisy room, non-native speakers experience more difficulties. This proved to be the most difficult environment. Phones and radios have a better signal to noise ratio. Communications through these means therefore generated fewer problems.


Not surprisingly, a situation involving a hearing-impaired non-native English listener in a noisy environment is most prone to difficulties.
Recent studies have shown that speech understanding and hearing loss can have significant impacts on other military operations (e.g. delay in casualty reporting time, delay in transport, reductions in lethality, survivability, and mission success in dismounted combat, and delays and errors in command and control operations). A better understanding of these communication challenges presents an opportunity to address them (e.g. through targeted training so that different accents/dialects are more easily understood) in order to reduce the impact that they could have on mission success in NATO operations.


Key take-away

Up to 20% of active duty Army soldiers have some degree of measurable hearing loss (HL). Six percent have clinically significant HL.


Non-native speech, hearing loss and noisy environments can and will have a cumulative detrimental effect on situational understanding.


Download Powerpoint Presentation: Human Factors in Medicine 285 Briefing – Col. LaKeisha Henry

Download Powerpoint Presentation: Auditory Considerations for Command and Control in Multinational Environments – Dr. Douglas Brungart

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