Say "si, Si"

In Spain they say "Si,si",
In France you hear "Oui, oui",
Ev'ry little Dutch girl says "Ja, ja",
Ev'ry little Russian says "Da, da"

But sweetheart, tell me why
No matter how I try
You won't answer to my plea,
Won't say "Yes" in any language to me,
When will you say "Si, si"?