Asturian and Cantabrian metaphony

In this short contribution the main characteristics of the metaphonic systems found in northern Spain are reviewed. Although in the dialect of Lena we find a typical shift chain by which the low vowel rises to mid and the mid vowels become high in metaphonic contexts, in other varieties phonemic boundaries are not crossed and instead distinct allophones are produced. I argue that these varieties present an earlier evolutionary stage and provide us with important clues on the origin of metaphonic shifts.