ただいまとおかえりの直訳は残念ながらありません。
皆ふつうに「ハァーイ！」と帰ってきますね。I'm homeも、言う人言わない人、いろいろいますが、とにかく”Hi！”ですね。
そのあとに自然な流れでHow was work/school today?のような会話が続く場合もあります。
いってきます、いってらっしゃいもそうです。
"Bye!" "Bye! Have a good day!" のような感じです。
上の先生に付け加えて。
オフィスに戻っても人の気配が感じられない時（部屋の奥に向かって）
I'm back.（ただいま戻りました～）とわざわざ知らせたい時などに使います。
それに対して
Hi, James.（ああ、ジェームズおかえり。）と返し
How was your day? と続けるとよいです。
Hi! は「ただいま」も「おかえり」も通じる便利なあいさつです。
A: Honey, I'm home from work
A: I'm back!
B: How was your trip to the beach?
A: I'm back!
B: Welcome back, my friend
A: Honey, I'm home from work（ただいま、仕事から帰ったよ）
A: I'm back!（ただいま！）
B: How was your trip to the beach?（ビーチはどうだった？）
A: I'm back!（ただいま！）
B: Welcome back, my friend（おかえりなさい）
Hello - greeting
I'm - I am
home - the place I live
------------------------------
I'm - I am
back - return
------------------------------
"I'm home" means "I have arrived at home"
------------------------------
I’ll be back in a minute.
Hello - 挨拶
I'm - I am
home - 住んでいる場所
------------------------------
I'm - I am
back - 戻る
------------------------------
"I'm home"は"I have arrived at home"（家に着いた）の意味です。
------------------------------
I’ll be back in a minute.（すぐに戻ります）
Honey, I'm home. - this is a very TV sitcom way of saying that you're home
Guess who's back! - this is a rhetorical question, so you're not really asking the other person to make a guess; you would say this excitedly as you enter the house; this is a common phrase to use when you come back home after being gone for a long time
Welcome home! / Welcome back! - to greet someone who just came back or just returned from abroad, you can say one of these
あまり日本のようにただいま、おかえりのように決まったフレーズはないように感じます。
日本語のただいまに近いニュアンスなのは I’m home!/I'm back. どちらも帰ってきたよ！という意味です。通常の挨拶のように、Hi!というだけの場合も多いです。
返し方としてはWelcome back!（おかえり)、Hi, Tim！(ティムおかえり）など
Did you have a good day?（いい一日だった？）
How was your day?(どんな日だった？）
What did you do today?(今日何したの？）
合わせて参考になれば幸いです。
*I'm home.
This is said by the person coming home. This is a way of announcing their presence.
*Welcome
This is said by the person who is already at home. It is way of welcoming them or showing them that you are happy to see them.
In Japanese, when someone comes home, the person coming home will say "tadaima" and the person/people who were already at home will say "okaeri". In English, the above examples illustrate typical comments which are similar.
I'm home! / Guess who's home!
** Used when you have been away from your home all day. (For example after work or after school).
I'm back! / Guess who's back!
**Used when you have stepped out of the home for a specific amount of time. (For example if you have to run errands or go to an appointment).
Welcome home!/ Welcome back!
Used by those that are home, to acknowledge that they have heard the person who arrived home.
When you return from somewhere you might say 'I'm back' to which the reply would be 'welcome back' if you return to your home you might say 'I'm home' and the reply would be 'welcome home'
These are the most common greetings we say in the UK to let the people already home know that you've come home.
Example -
"Hello, I'm back from the shop" or you could say "Hello, I'm home from work"
これらは、ただいまを表すイギリスで最も一般的に使われるフレーズです。
例：
"Hello, I'm back from the shop"
（やぁ、お店から戻ったよ。）
"Hello, I'm home from work"
（やぁ、会社から帰ったよ。）
When you get home from work or some place, you can use the following phrases "I'm home" and "I'm back".
For example, you can use these phrases in a sentence in the following ways:
-Honey, I'm home. I cannot wait to eat the dinner that you made for me.
-Mom, I'm back. School was great today.
仕事などから家に帰ってきた時は、「I'm home」や「I'm back」が使えます。
文章の中では以下のように使えます：
-Honey, I'm home. I cannot wait to eat the dinner that you made for me.
（ただいま。夕御飯がすごく楽しみだよ）
-Mom, I'm back. School was great today.
（ただいま。学校は今日最高だった）
アメリカ合衆国 
日本 
ニュージーランド 
南アフリカ 
イギリス 
カナダ 
