You may say 'omedetou.'
omedetou
On your grandchild's what? Be specific to get specific answers. Anyways that would be:'Mago-san no koto omedetou gozaimasu'.
Felicitaciones por su compromiso.
we say Nakagawa if we want to say inside in Japanese.
メロン is how you say melon in Japanese.
congratulations on.
No, you cannot say, they send their congratulations. You have to say they sent their congratulations.
omedetou
congratulations
"Proficiat" is how you say congratulations in Flemish.
no flowers say congratulations
In Filipino, you would say "Congratulations" as "Congratulations" or "Pakaka-bait."
You can say "čestitke" in Bosnian to say congratulations.
In Hindi, you can say congratulations by saying "बधाई हो" (Badhai ho).
"félicitations"Congratulations is 'félicitations' in French. You can also use congratulations (same orthograph), but this is much less in use.
congratulations on your wedding
Ho'omaika'i means congratulations.