Middle English q

[Niedokonany]

The sporadic <au> for Modern English <a> before /n/ (straunge, Caunterbury), what did it indicate? Was there a diphthong in those words or maybe a back rounded vowel? I've been toying with an alternative orthography dating back to that period and I'm not sure how to transcribe the mentioned words.

[Thry]

Good question. Could it be nasalization? Or the rendering of a nasalized borrowing? [apparently straunge comes from Anglo-Norman estraunge, but idk what that means]