Knusper, knusper, Knäuschen, wer knuspert an meinem Häuschen? Nibble, nibble, gnaw, who is nibbling at my little house? Knäuschen has no real meaning today, just there to rhyme with Häuschen. The etymological origin helps to understand it better, knuspern is onomatopoeic (nibbling) and knäuschen is related to Knust and Knaust and both mean breadcrumbs. Knausern means as well 'save with bread'.