No, it's not an umlaut.
Umlaut is, to quote an unreliable source called Wikipedia, a sound change in which a vowel is pronounced more like a following vowel or semivowel
. The word also refers to the two dots placed over a vowel to indicate that sound change. It is not something that occurs in English words, except loanwords.
If you've been pointed to this page, it's probably because you asked someone "Why did you use an umlaut there?" when they said something like "coöperate". What that person has used is a diaeresis. From that same unreliable source, a diaeresis, while visually identical to an umlaut, is used to mark the separation of two distinct vowels in adjacent syllables when an instance of diaeresis (or hiatus) occurs, so as to distinguish from a digraph or diphthong
. Diaereses are both unambiguous and consistent. Where "cooperate" could also be pronounced /ˈkuːpəreɪt/, like cooper, "coöperate" is unambiguous. And the more common approach of "co-operate" is annoyingly inconsistent. A hyphen should represent something semantically, not simply a case where not using a hyphen would be confusing. We don't use a hyphen in most other words starting with "co", and in fact in many it would be confusing to do so, like co-rrespond.
| Pros | Cons |
|---|---|
| Unambiguous | |
| Consistent | |
| Classy | having to copy-paste the letter-diaeresis pairing every time, because let's be honest, some of us are native English speakers with no reason to include diacritics on their keyboard and the linguistic diversity of a bowl of unseasoned oatmeal, leading to fumbling with the ALT-key Windows pairings or something and wishing you just had a little plug-in keyboard you could use for all your pretention needs |
| Feel like you write for The New Yorker | |
| Pretentious as fuck | |
| Get to link people to this wonderful essay when people ask why you used an umlaut |
| Broke | cooperate |
|---|---|
| Woke | coöperate |
| Bespoke | coäuthor |
| Bespokeër | makeüp |
| Bespokeëst | tacoÿ (to describe something similar to a taco) |
This page is also a template!
{{User:Tamzin/The diaeresis|de|o|versighted}}→ deöversighted- The template diaeresisifies the second argument, assuming it is a single character, and links it back to this page.
Known diaeresis users
Either these users are sockpuppets of one another, or they're all just very pretentious. 
Inconclusive.
- -- Tamzin[cetacean needed] (they|xe)
DiaeresisDiæresisDiaëresis-lovers of the world, unite! Extraordinary Writ (talk) 23:28, 24 June 2022 (UTC)- Pretension is my brand, after all. MastCell Talk 17:28, 28 June 2022 (UTC)
- dyïng (talk) 00:15, 1 November 2022 (UTC)