Before revision: This apparent irregularity is explained by positing that these words were borrowed into Standard English from a regional dialect in which /f/ did regularly become /v/ (such as West Country English), while other words containing /f/ were not so borrowe
After revision: This apparent irregularity is explained by positing that these words were borrowed.d into Standard English from a regional dialect in which /f/ did regularly become /v/ (such as West Country English), while other words containing /f/ were not so borrowe