As we may all know, ligatures and diæreses have long become obsolescent. However, I see the logic behind spelling words with ligatures and diæreses. For example: algæ, formulæ, æon, æqulateral, æternal, œuvre, œsophagus, fœderal, coöperation, aëroplane, etc.

Is it acceptable that I spell similar words as such (i.e. in modern use: papers, theses, publications)? Are there any disadvantages or drawbacks?

If I do spell these words with ligatures and diæreses, does it mean that I have to use obsolete spellings for all the words or I can choose?

If spellings such as paediatric, foetus, anaesthesia are encouraged in BrE (and medical/formal contexts), does it mean that all the other words should be spelt with ae or oe as well?

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    The biggest difficulty is the inability of others to edit or quote your work in the same form, since this use is beyond many typographical systems, or at least the skill of the operator. And you do not explain the logic that you say you see, especially with regard to ligatures.
    – bib
    Commented May 20, 2016 at 20:15
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    @ProfYaffle I use ligatures and diaereses for the same reason that I comb my hair, and eat with a knife and fork. It is out of respect for the culture into which I was born.
    – WS2
    Commented May 20, 2016 at 20:51
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    Are we all talking about the same thing here? I read the OP as talking about single fused glyphs like æ, instead of the two distinct typed characters like ae in words like æon/aeon. I propose there are three spelling modes -- archaic, British, and US -- as in encyclopædia / encyclopaedia / encyclopedia. The question is whether the archaic form is acceptable, right? Commented May 20, 2016 at 21:05
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    When I see these types of constructs in written in modern (American) English, I generally consider the writer to be a pompous twit bent upon impressing the unwashed with his or her mad writing skillz. It thus detracts from the message.
    – Tony Ennis
    Commented May 21, 2016 at 15:48

3 Answers 3


Ligatures and diaereses are not generally used in modern English text. However, whether or not they are "acceptable" depends on many factors.

The easiest way to judge if something is acceptable is if you have an institutional style guide that you're supposed to follow. Any reasonably complete style guide should cover this topic. I believe the most common practice in formal contexts is to only use ligatures and diaereses in words from foreign languages, not including Greek or Latin (so œuvre might be spelled with a ligature, and Noël might be spelled with a diaeresis) and in official names such as Encyclopædia Britannica. The New Yorker still uses the diaeresis to indicate hiatus in some English words such as coöperation, but this is unusual and perceived as quaint. I don't think even they would use a diaeresis in aëroplane since the second vowel in this word is elided for nearly all speakers.

In words from Latin or Greek, the ligatures æ œ will be perceived as stylistic variants of the digraphs ae oe. These ligatures are not generally used in modern typography.

Words that can't have a ligature because they are spelled with e

Several of the words you listed in your original question are never spelled with a ligature or a digraph in Modern English. Æquilateral/aequilateral, æternal/aeternal, fœderal/foederal are all entirely obsolete. These words are always spelled equilateral, eternal, federal. You can find out which spellings are in general use by looking up the word in a dictionary.

All modern English is inconsistent in this regard: while the specifics vary, both Brits and Americans can only have ae/oe in some words, and can only have e in others. You should not try to spell consistently based on the etymology: there is no way to do this without using non-standard spellings.

Words where you can choose between e and ae/oe

You only have a choice for some words. For example, æon and œsophagus may be written with just e or with a digraph (rendering these digraphs as ligatures would not be usual style, but it would not look too strange in my opinion). In some cases, one choice is standard for a particular variety of English (for example, oesophagus is standard in British English but not in American English).

  • To recapitulate, can I spell words spelt with ae and oe with ligatures?
    – Veo
    Commented May 21, 2016 at 7:53
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    @Veo Yes, if it's consistent with your style guide (your own or that of whatever body governs what you're writing). It would be unusual in normal use, and would be seen as a little archaic, but if it's part of the normal look-and-feel then I'd say it's acceptable. In normal life, though, it would be seen as a bit of an affectation (like spellings such as demesne and faerie - both of which I would use, however :) ). Commented May 21, 2016 at 8:30
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    It's merely quaint when The New Yorker writes "coöperation." From almost anybody else using US English, it's an affectation that would make me question why the writer felt compelled to do that. If you insist on spelling "federal" as "fœderal" and you aren't intentionally putting on an archaic air (or quoting an original text), you simply look foolish. Commented May 21, 2016 at 9:41

It's no longer acceptable or helpful;

It's so old-fashioned that it has become an affectation, and will result in your writing being judged poorly.

It's acceptable if you're quoting a language that uses them (that is, if you'd also italicise the word to show it's a foreign word) but modern English doesn't have them.

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    The OP was asking about ligatures and diaereses: the latter are very current and correct, at least in BrE. Indeed, the former remain correct in some style guides as well, e.g. p23: ox.ac.uk/sites/files/oxford/media_wysiwyg/… Commented May 20, 2016 at 21:19
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    P23 has non-ligatured forms like 'formulae' at 8 characters. Did I miss something? Was expecting to see something like 'formulæ' (7 characters) Commented May 20, 2016 at 21:26
  • Also, I don't think I've ever seen 'coöperate' or 'aëroplane' in Britain. Commented May 20, 2016 at 21:29
  • You missed "archæology, hæmatology, orthopædics" on the preceding page.
    – herisson
    Commented May 20, 2016 at 22:47
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    Is the "Association of Art Editors" (apparently an American organization) an authority on "English", or on "American English"? Or haven't they noticed that other countries (Britain, Canada, Australia, etc) use a different spelling conventions?. Also, I'm reluctant to accept the idea that the Wikipedia guide is an authority on anything except Wikipedia.
    – alephzero
    Commented May 21, 2016 at 0:51

One of the advantages of using non-WYSIWYG typesetting software such as LaTeX is that it takes care of ligatures for you (and respects the style settings put in effect by the journal editor).

See https://tex.stackexchange.com/questions/tagged/ligatures

This won't automatically produce any of the ligature examples in your question, probably because they aren't proper style in modern formal writing.

  • Yeah - this does things like the 'fi' ligature, which is a pleasant holdover from moveable type, right? Commented May 20, 2016 at 21:31
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    @Steve: Correct.
    – Ben Voigt
    Commented May 20, 2016 at 21:32
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    I think that only your last sentence here is really relevant to the question. Commented May 21, 2016 at 1:02
  • The fi ligature is a typographic ligature, not a lexical one. I would not expect LaTeX (or any typesetting system) to add lexical ligatures.
    – TRiG
    Commented Oct 15, 2020 at 11:02

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