patter (1) Look up patter at Dictionary.com
"make quick taps," 1611, freq. of pat (n.).
patter (2) Look up patter at Dictionary.com
"talk rapidly," c.1400, from pater "mumble prayers rapidly" (c.1300), shortened form of paternoster (q.v.). Perhaps influenced by patter (1). The noun is first recorded 1758, originally "cant language of thieves and beggars."