Japanese are very dicipline where they will wish everyone whenever they meet in the morning, afternoon and night.

Good Morning – Ohayō Gozaimasu　（おはようございます）
Good Afternoon – Konnichiwa　（こんにちは）
Good Evening – Konbanwa　（こんばんは）
Good Night – Oyasumi Nasai　（おやすみなさい）

There is another type of wishes where Japanese family will normally say :
When you are going out from home, dormitory, office, etc
You should say : Itte Kimasu （いってきます）- I’m going out
They should reply : Itte Rasshai （いってらっしゃい）- Take care yourself

When you return home, office, dormitory, etc
You should say : Tadaima （ただいま）- I’m Home
They should reply : O Kaeri Nasai （おかえりなさい）- Welcome Back

Based on the above, you may notice that some word has a double character like “itte” & “rasshai”. This will happen whenever there is a small “tsu”.
Example : itte （いって）and rasshai （らっしゃい）

To understanding further on the pronunciation, visit HERE