de doux rêves, de beaux rêves
sweet dreams are 'de beaux rêves' in French.
If you want to tell someone "sweet dreams," you can say "fais de beaux rêves."
Fais de beaux rêves
You could say either, but the traditional good-night phrase is "Sweet dreams."
good night and sweet dreams my friends (a French would say 'de beaux rêves' and not 'doux rêves')
sweet dreams
"toi aussi, fais de beaux rêves"
bonne nuit et doux rêves (:
To say, "have sweet dreams" in Welsh is "cewch breuddwydion hyfryd"
To say "sweet dreams" in Portuguese, you can say "sonhos doces."
Codladh sámh ort
Sweet dreams translates to drøm sodtin Danish.