For a wish, Finnish takes the conditional and adds a little sigh. There are two common ways:

Finnish	English
Olisipa jo kesä!	If only it were summer already!
Kunpa minulla olisi enemmän aikaa!	If only I had more time!
Voisinpa nukkua vielä tunnin!	If only I could sleep another hour!

• -pa / -pä glued to the conditional verb, which comes first: olisipa, voisinpa, tietäisipä.
• Kunpa at the start, with the conditional later in the sentence.

Both mean the same: I wish…, if only…. A plainer, everyday version is Toivoisin, että… — I'd hope that…