This is the 15th most frequent Finnish word.
kanssa
"With."
‘kanssa’ is used here to indicate accompaniement, specifying that the action is performed together with friends.
Haluaisin lähteä rannalle ystävieni kanssa.
I would like to go to the beach with my friends.
‘kanssa’ specifies the company during the visit to the theater, showing it's a shared experience.
Kävin teatterissa serkkuni kanssa viime viikonloppuna.
I went to the theater with my cousin last weekend.
‘kanssa’ is used to show that the enjoyment of the trip involved the company of her dog.