The verb jankata means "to say the same thing over and over in an insistant manner":
Aina hän jankkaa sitä samaa asiaa!
= She's always saying the same thing!
Kärhämä is a folk music group that sings about the etymologies or origins of Finnish words. Here's their version of the origin of jankata, based on the brand new research article "Suomen Jankata" by Jeongdo Kim (2020), with subtitles in English!
"Stubbornly insisting, arguing,
Harping on the same old barking
Yakking like a false sonata
That’s the tone of the verb jankata!"