Greetings and Daily Expressions

Ohayou gozaimasu. 　おはようございます - (Good Morning)
Konnichiwa. 　こんにちは。-　(Hello/Good afternoon.)
Konbanwa. 　こんばんは。-　(Good evening.)
Oyasuminasai. 　おやすみなさい。-　(Good night.)
Unlike English, it is mostly used before going to bed, but you can say it when your friend live to go home after party for example.
Itte kimasu いって　来ます　ー'll be back when leaving (and planning to return)
Itte rasshai いって　らっしゃい　-（Good bye )go and return -the reply to "ittekimasu", said to the person leaving
Tadaima ただいま　（I'm back )ー　by the person returning home
Okaeri nasai おあ帰りなさい　-(Welcome home ) the reply to "tadaima", to the person returning
Okaeri　お帰り - same as okaerinasai, but this non formal use.
Ogenki desu ka - お元気ですか　－ (are you well / how are you)
Doomo arigatoo gozaimasu どうも　ありがとう　ございます。- (Thank you very much)
Doo itashimashite どう　いたしまして　－　(you are welcome ) to reply arigatou
jya mata ne - じゃ　またね -　(see you)- non formal use
mata ashita - また　明日 - (see you tomorrow) - formal use

note :
People do not say "sayonara（さよなら）" when leaving their own home. "Ittekimasu（いってきます）" is normally used. The response to "Ittekimasu（いってきます）" is "Itterasshai（いってらっしゃい）". "Dewa mata（ではまた）or jya mata(じゃ　また）" is also often used as "see you later", similar to the English expression.

Read more »

Japanase Greating

Good morning = ohayo gozaimasu (おはよう　ございます）
One can also say just "Ohayou（おはよう）". This is casual, and should not be used with one's boss.

Good afternoon, Hello = konnichiwa　（こんにちは）

Good evening = konbanwa　（こんばんは）

Goodnight = oyasumi nasai　（おやすみなさい）
Unlike English, it is mostly used before going to bed.

Goodbye = sayonara　（さようなら）
Sayounara（さようなら)" can be also used instead of "sayonara（さよなら)." People do not say "sayonara（さよなら）" when leaving their own home. "Ittekimasu（いってきます）" is normally used. The response to "Ittekimasu（いってきます）" is "Itterasshai（いってらっしゃい）".

See you later = dewa mata nochihodo　（では　また　のちほど）
"Dewa mata（ではまた）" is also often used as "see you later", similar to the English expression

How are you? = o genki desu ka　（お　げんき　ですか）

Fine, and you? = genki desu. anata wa　（げんきです、あなたは）

Pleased to meet you = hajimemashte（はじめまして）

My name is _____ = watashi wa _____ desu（わはしは　＿＿　です）

Excuse me = sumimasen　（すみません）

I'm sorry = gomen nasai（ごめんなさい）
(eg I trod on your foot)

Thank you
domo　（ども）
arigato（ありがとう）
arigato gozaimasu（ありがとう　ございます）
domo arigato gozaimasu（ども　ありがとう　ございます）
(in iincreasing order of formality)
You're welcome = do itashimashte（どう　いたしまして）

Read more »