Sawatdee khap!
sweet dreams? well you can say 'fun Dee' which is more accurately 'good dreams' (Dee meaning good) and you would add 'na' on the end to soften it a little as in to a friend, if you wanted to be polite as well you could say 'fun Dee na Khap/Ka' (khap if you are male and ka if you are female)
sweet is 'waan' as in 'baak waan' or sweet mouth which is what you will be called if someone thinks you are sweet-talking them.
not sure if the term 'fun waan' is used or not. Also please bear in mind that writing Thai words in romanised letters does not give an accurate description of the correct pronunciation. For that you really need to learn Thai script as it has all the tone marks to show you how the word should be pronounced and which tone to use with each word.
Therefore there may be some who will disagree with how I've written the Thai words here :-)
sawatdee khap, fun Dee na khap ;-)
To say, "have sweet dreams" in Welsh is "cewch breuddwydion hyfryd"
In Thai, "good night" is expressed as "ราตรีสวัสดิ์" (pronounced "raa-tree sa-wat"). It's a formal way to wish someone a good night. You can also simply say "ฝันดี" (pronounced "fan dee"), which means "sweet dreams."
dobra noc
If you want to tell someone "sweet dreams," you can say "fais de beaux rêves."
Not sure about 'sweet dreams' exactly, but 'SpakOini NOchi' (conventionally 'good night') is literally '(I wish you) a tranquil night'
sweet dreams
To say, "have sweet dreams" in Welsh is "cewch breuddwydion hyfryd"
To say "sweet dreams" in Portuguese, you can say "sonhos doces."
Sweet dreams translates to drøm sodtin Danish.
sweet dreams are 'de beaux rêves' in French.
You can say "Lijepi snovi" in Bosnian, which translates to "sweet dreams" in English.
"মিষ্টি স্বপ্ন" (Mishti Shapno) is how you say "sweet dreams" in Bengali.
You can say "matamis na mga pangarap" in Tagalog, which translates to "sweet dreams" in English.
Sweet dreams translates to punjara swapnangal in Malayalam.
You could say either, but the traditional good-night phrase is "Sweet dreams."
How do you say good night sweet dreams in Patois
Doces sonhos. Or Tenha doces sonhos (if you are wishing sweet dreams)