What is the language policy in NATO's multinational battlegroups?

NATO has two official languages: English and French. That is the official policy.

The working language for most headquarters and units is English; however, all strategic documents have to be published in BOTH English and French.

The "official type of English" is British English, so spelling is done in the "Queen's English" so works like defense vs defence and maneuver vs manoeuvre

At the NATO Battlegroup level (which is tactical) English is the common language that is used when communicating in a written or verbal manner. They do not use French (unless you are a French speaking contingent within a battlegroup that uses it for internal communication). Most Europeans in their nations' military have working basic English with the vast majority of officers being bilingual as a requirement to be an officer.

Source: first hand experience in NATO BGs

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