One early difference shared by the West Germanic dialects is the monophthongization of unstressed diphthongs. Unstressed *"ai" became "ē", as in "haitē" (Kragehul I) from Proto-Germanic *"haitai", and unstressed *"au" likewise became "ō". Characteristic is also the Proto-Norse lowering of Proto-Germanic stressed "ē" to "ā", which is demonstrated by the pair Gothic "mēna" and Old Norse "máni" (English "moon"). Proto-Norse thus differs from the early West Germanic dialects, as West Germanic "ē" was lowered to "ā" regardless of stress; in Old Norse, earlier unstressed "ē" surfaces as "i". For example, the weak third-person singular past tense ending "-dē" appears in Old High German as "-ta", with a low vowel, but in Old Norse as "-ði", with a high vowel.