Original: While emir is the predominant spelling in English and many other languages (for example, United Arab Emirates), amir, closer to the original Arabic, is more common for its numerous compounds (e.g., admiral) and in individual names.
Simplified: Emir is the most common spelling in English and many other languages (for example, United Arab Emirates). The spelling amir, that is closer to the original Arabic, is more common for its compounds (e.g., admiral) and in individual names.