'Grandson' = 'barnebarn'
As in 'see you later?' You may say 'jaa, [mata] ne.'
Japanese would say sashiburi
Grandson in Ukrainian is внук (vnuk).
Grandson in Russian is внук (vnuk).
In Hindi, 'grandson' is said as "पोता" (pota).
Miru koto wa dekimasen
see Google Translate
Yurei wo Miteita!
You may say 'Eiko ni aitai.'
petit fils is the text translated in French. This is the text translated from Grandson.
Unokája