The Uerdingen Line is the isogloss within West Germanic languages that separates dialects which preserve the -k sound in the first person singular pronoun word "ik" from dialects where the word-final -k has changed to word final -ch in the word "ich". This sound shift is the one that progressed the furthest north among the consonant shifts which characterize High German and Middle German dialects. The line passes through Belgium, the Netherlands, and Germany.