The word Borbhan comes from Gaelic. It’s the gentle murmuring or purling sound made by a stream; also the sound of small stones falling.
”Help me to tune my doleful notes to gurgling sound Of Liffey’s tumbling streams: come, let salt tears of ours, Mix with his waters fresh.” – Edmund Spenser, 1595
Kletteren is a Dutch word that’s similar in meaning. It’s perfectly onomatopoeic because it means the sound of both water and stones tinkering and clattering together at a fast pace.