Aloha po
Subho ratri............But that is beyond formal.....We just say GoodNight in daily conversation.
You can say "tenha uma boa noite".
aloha po or aloha aumoe (if going to bed) [aloha po] [aloha ow-mo-ay]
In Thai, you can say "ราตรีสวัสดิ์ที่รัก" (raatree sawatdii thii rak) to mean "goodnight my love." The phrase combines "ราตรีสวัสดิ์" (raatree sawatdii), which means "goodnight," with "ที่รัก" (thii rak), meaning "my love." It's a sweet and affectionate way to bid someone goodnight.
Kakalina is Kathy in Hawaiian
You can say "lafi" to say goodnight in Mandinka.
In Berber, you can say "tanemirt" to say goodnight.
goodnight
"Goodnight".
goodnight!
In Fulani, you can say "Jaama wolof" to say goodnight.
In Pangasinan, you can say "napagtolak" to mean goodnight.
shab bekheyr
In Polish, you say "dobranoc" to wish someone goodnight.
In British English, you can say "goodnight" or "night" as a shorter version.
In Sondhi, you can say "ດີ່ນກັນ" (dien kan) to say goodnight.
goodnight is "bonne nuit" in France.