Do you have another job? = 他の仕事持っていますか
Are you also working another job? = 他の仕事もやっていますか
Besides this job は「この仕事以外に」です。例えば "besides this job, are you also working another job?"
聞きづらい質問の前に "if you don't mind me asking" (聞いてもよろしければ)を使うとより丁寧に聞けますよ！
Asking about employment is a sensitive topic and some teachers may feel uncomfortable answering a questions like this, especially if they feel like it might not be seen as a good thing. It may be a good idea for you to explain why you are asking so that they feel more comfortable answering. I hope that this helps. :)
Do you have another job? （他に何か仕事をされていますか？）
another=ほかに
job=仕事
Are you only working as an English tutor? （英語講師としてだけ働かれているのですか？）
working=働いている
as=～として
tutor=家庭教師、講師
聞いてもいいのか迷った場合は If I may ask,...「もしお聞きしてよければ、聞いても差し支えなければ」と付け加えてみてはどうでしょうか。文頭、文末どちらにつけてもいいです。
If I may ask, how many are in your family?
聞いても差し支えなければ、ご家族は何人ですか？
少しでも参考になれば幸いです。
Are you only working as an online tutor? - a polite way of asking if this is their only job.
Do you have another form of employment? - another polite way of asking if this is their only job, however this one is more informal.
Are you only working as an online tutor?（オンライン講師の仕事しかしていませんか）
- それがその人の唯一の仕事なのか丁寧に尋ねています。
Do you have another form of employment?（他に仕事はしていますか）
- 同じく、それがその人の唯一の仕事なのか丁寧に尋ねています。しかし、こちらの方がインフォーマルです。
First, let me be explicit and tell you that it is NEVER considered polite or respectful to ask somebody "What else they do for work". The reason for this is that it implies what they are doing now, i.e. teaching you English, is not a good enough career. I would avoid asking this question as there is no respectful way to ask it. If you feel you must know what else they do to make money you can ask.
What else do you do?
Do you have another occupation?
Is this your only job?
まず、はっきり言わせてください。「他に何の仕事をしていますか」と人に尋ねるのは決して丁寧、礼儀正しいとは見なされません。なぜかというと、その人が今していること、つまり英語を教えること、が不十分な職業だというニュアンスになるからです。この質問には礼儀正しい言い方というのがないので私だったら聞きません。もしどうしても聞かないといけないと思うなら、次のように言えます。
What else do you do?（他に何の仕事をしていますか）
Do you have another occupation?（他に何か仕事をしていますか）
Is this your only job?（仕事はこれだけですか）
To ask someone politely and informally, you can use these two expressions and as your teacher knows you are learning English I am sure they would understand you are not being disrespectful.
-Do you have another job?
-Do you do anything else?
丁寧そしてカジュアルに尋ねるなら、これら二つの表現が使えます。先生はあなたが英語を勉強中であることを知っているので、ばかにしようとしていると思うことはないでしょう。
-Do you have another job?（他の仕事はしていますか）
-Do you do anything else?（他のことはしていますか）
If you ask in this way, your tutor will know that you are trying to be polite, and might answer your question even if he / she doesn't really want to. If you use this question form, you give your tutor (or anyone else from a different cultural background) a way to refuse your request politely.
1) If he / she doesn't want to tell you, since this is a personal question, he / she might answer, "Yes, I do mind."
2) He/ she might answer, "I would rather you didn't ask."
上記のように言うと、相手の講師の方にこちらが礼儀正しく聞こうとしていることが伝わり、たとえ本心はそうでなくても質問に答えてくれるかもしれません。
上記のような形式で聞くことで、相手（講師であれ誰であれ）にその質問を丁寧に拒否する選択肢を与えることができます。
1) 聞かれた相手が個人的な質問なので答えたくないというときは、"Yes, I do mind."（答えたくありません）と答えるかもしれません。
2) こちらには、"I would rather you didn't ask."（答えたくありません）と答えるかもしれません。
To your online English teacher, you want to ask if they have another job. In a polite and respectful way. In that case, you can try one of the above-suggested example sentences which may be appropriate for any given situation. There are always a variety of ways to respond to someone or make a comment - depending on the context and other factors such as nationality, appropriacy and body language
These are two appropriate questions that you could ask a teacher to see if they have another job outside of online teaching. One question has more of a focus on, "another job," or a second job whereas the other more asks the question about the current job as an English teacher.
Do you have another source of income besides this one?
If you want to ask your teacher if he or she has another form of employment, you can ask in either of these ways. They are both quite direct questions and appropriate enough for the situation. Some teachers may not want to answer because they may find it a little offensive. Be cautious when asking these questions.
"Aside from" is another way of saying "apart from" or "in addition to"
"Apart from this, do you have any other hobbies"
A "source of income" is basically a place where more income or money comes from. It is a little less casual and more formal.
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