Cortana is available in the following countries/regions: China, France, Germany, Italy, Spain, United Kingdom, and United States. Cortana is available in these languages: Chinese (Simplified), English (U.K.), English (U.S.), French, Italian, German, and Spanish
Windowsの携帯電話用のコルタナをご覧ください 8.1 特徴 : Windowsの携帯電話にコルタナを使用する方法
To use Cortana, all these settings must be set to the same language:
- Languages (this is your device language).
- Speech language (language pack must be installed).
- Country or region
注意: If you change your region, you might not be able to shop at Store, or use things you’ve purchased, like memberships and subscriptions, games, movies, TV, and music.
Hope this information helps.