Mi casa, tu casa.
Bienvenidos
In Mexican Spanish, you can say "bienvenido de regreso."
You can say "Witaj" or "Witajcie" to say "Welcome" in Polish.
It is more common to say "Welcome to the..." when welcoming someone to a specific place or event.
Bienvenidos a nuestra casa
It can be correct to say you are always welcomes. It is correct when finished with "in my home or at my place of business."
bienvenidos
Bienvenidos
Bienvenue dans ce lieu
Translation: bienvenido
the official language in Mexico is spanish. welcome in spanish is bienvenido.
you say welcome aboard I don't know why but that seems to be the case