"rough sound of the letter -r-" (especially that common in Northumberland), 1760, later extended to "northern accented speech" in general. Possibly the sound of the word is imitative of the speech peculiarity itself, or it was adapted from one of the senses of bur (q.v.), perhaps from the phrase to have a bur in (one's) throat (late 14c.), which was a figure of speech for "feel a choking sensation, huskiness." OED says the Scottish -r- is a lingual trill, not a true burr.
雙語例句
1. I take it you're a friend of the Kellings, Mr Burr.
伯爾先生，想必您是凱林家的朋友吧？
來自柯林斯例句
2. She speaks with a soft West Country burr.
她說話帶有一種西部地區濃重r音的口音。
來自《權威詞典》
3. She speaks with a Scottish burr.
她講話時帶蘇格蘭人的顫音r音.
來自《簡明英漢詞典》
4. The last part introduces the burr _ distribution with three parameters.