You can simply call this person "Norwegian British". If you want or need to you can go into detail about the person saying, "She is from the UK but is from Norwegian descent." Or explain the persons heritage and descent (where they come from, their genetics).
シンプルに「Norwegian British」と言えます。
もう少し詳しく言うなら：
"She is from the UK but is from Norwegian descent."
（彼女はイギリス出身だけど、祖先はノルウェー人です）
または、その人の家系、祖先について説明します。
"Norwegian British"- This explains that the person has nationality from both Britain and Norway.
"I am Norwegian but I am from the UK" This explains that the person is Norwegian but lives in the UK.
"I am Norwegian but live in the UK" This is another way of explaining to a person that your nationality is Norwegian but at the moment you live in the UK.
"Norwegian British" - イギリス・ノルウェー両方の国籍を持つ人を表します。
"I am Norwegian but I am from the UK"
（私はノルウェー人ですが、イギリス出身です）
↑ノルウェー人だけどイギリスに住んでいる、という意味です。
"I am Norwegian but live in the UK"
（私はノルウェー人ですが、イギリスに住んでいます）
↑これも、国籍はノルウェーだけど現在イギリスに住んでいる、と伝える言い方です。
Well someone may be born in Norway of British parentage, or born in Britain and of Norwegian parentage. Either way, it is a mixture of two countries or parents or geographical position in some way!
A person of Norwegian descent living in Britain may be referred to as:
-Norwegian British
-A Norwegian person living in Britain
You may use these terms in a sentence in the following ways:
-Sam is Norwegian British. His parents moved with him to Britain when he was 7 years old
-My colleague is a Norwegian person living in Britain
「イギリスに住むノルウェー人」は次のように言えます。
-Norwegian British
-A Norwegian person living in Britain
これらのフレーズは文の中では次のように使えます。
-Sam is Norwegian British. His parents moved with him to Britain when he was 7 years old
（サムはイギリス出身のノルウェー人です。彼の両親は彼が7歳のときにイギリスに移住しました）
-My colleague is a Norwegian person living in Britain
（私の同僚はイギリスに住んでいますがノルウェー人です）
"British Norwegian" can be used to describe a person who has both UK citizenship as well as Norwegian citizenship OR be a UK citizen of Norwegian ancestry/decent.
"Norwegian British"
This is the generic term for someone who is or Norwegian heritage, a native of Norway, but it living in the United Kingdom
ex. "I am a Norwegian British studying chemistry at Oxford University"
"Norwegian British"（イギリス出身のノルウェー人）
これは「イギリスに住むノルウェー人」の一般的な言い方です。
例：
"I am a Norwegian British studying chemistry at Oxford University"（私はイギリス出身のノルウェー人です。オックスフォード大学で化学を学んでいます）
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