My Japanese English teacher helped me to understand grammar better.
A person who is both Japanese and an English teacher can be described as "a Japanese English teacher". The nationality (which is a adjective) would come first before the profession (which is a noun), for example: "a French artist", "a Canadian musician", and so on.
日本人の英語の先生は、"a Japanese English teacher"と言うことができます。国籍（形容詞）は、職業（名詞）の前に来ます。例えば：
a French artist（フランス人の芸術家）
a Canadian musician（カナダ人のミュージシャン）
など。
You can be a teacher of a language as long as you can speak it well enough to teach someone else.
So your teacher could be from/born in Japan but can teach English as well.
So you could say " My English teacher is originally from Japan." meaning thats where they come from or they were born there.
人に教えられるだけ流ちょうに言葉が話せれば先生になれます。
ですから、日本出身の英語の先生もいます。
下記のように言えます。
My English teacher is originally from Japan.
（私の英語の先生は日本の出身です）
これは、先生の出身地について言っています。
English teachers live in many different countries if you can speak and understand the rules of English, you can teach it too.
"My English teacher is Japanese!"
"I have a great English teacher! He was born in Japan and speaks fluent Japanese!"
'A Japan-born English teacher - great! Is his ethnicity Japanese?"
"No, his parents are English."
"Oh, I have a Japanese English teacher, but his ancestry is totally Japanese."
"I have a great English teacher! He was born in Japan and speaks fluent Japanese!"
良い英語の先生みつけたんだ！日本人で、しかも日本語ベラベラなんだ！
'A Japan-born English teacher - great! Is his ethnicity Japanese?"日本生まれの英語教師ね、いいじゃん！人種的にも日本人なの？
"No, his parents are English."いや、両親はイギリス人だって。
"Oh, I have a Japanese English teacher, but his ancestry is totally Japanese."へえ、僕も日本人の英語教師知ってるけど、彼は先祖代々日本人だね。
An English teacher whose nationality is Japanese can be called a "Japanese English teacher" or an "English teacher of Japanese descent".
For example, you can say:
-My English teacher is of Japanese descent.
日本国籍の英語の先生は、Japanese English teacher、またはEnglish teacher of Japanese descentと言うことができます。
例えば、次のように言えます。
-My English teacher is of Japanese descent.
私の英語の先生は、日系です。
日本 
アメリカ合衆国 
イギリス 
南アフリカ 
