The Royal Air Force is promoting the use of gender-neutral pronouns to encourage inclusion and diversity across the service.
Alternative pronouns to 'he', 'she', 'him' and 'her' include 'Ze', 'Per' and 'Hir'.
The language system will be launched within the service rank and title protocol, which could have previously seen female officers referred to as 'Sir'.
Under the new environment, a Leading Aircraftman could be referred to as a Leading Aircraft-Per.
A Royal Air Force spokesperson said: "The RAF actively promotes diversity and inclusion throughout its ranks in a number of ways.
"The open and transparent sharing of chosen pronouns is one way we can be an inclusive employer."
The RAF Gender Network launched in July this year, and has already hosted webinars on gendered language and organisational change.
A wider drive for inclusivity will also see the service broaden its policies on hair styles and headdress.
Cornrows, twists and braids are now permitted, but must be tied back if the length passes the bottom edge of the service jacket collar.
Turbans of an approved pattern and colour and with a fitted cap badge can be worn instead of uniform headdress.
"The RAF has revised its hair policy to maintain high standards of appearance whilst being inclusive of different hair types and cultures and to reflect the society it is charged to protect," said a spokesperson.
"This is one important step, of many, to deliver a fully inclusive next-generation Air Force fit for the 21st century."
Cover image: MOD.