"a Euler graph" or "an Euler graph"?

Question

I recently referenced the following article in my manuscript.

S. Toida, Properties of a Euler graph, J. Franklin Inst. 295 (1973) 343–34.

However, my grammar checker flagged “a Euler graph” as a grammatical error, stating that it should be "an Euler graph." I am confused as to whether both forms are acceptable and whether it is appropriate to respect the original intention when encountering potential errors in titles when citing.

Edit: I noticed some conflicting opinions in comments. I'm uncertain about which suggestion is the best. John Bentin 's answer seems to be the most convincing.

Answer 1

There are two questions here. The first is easily answered: Is “a Euler graph” correct? No. It should be “an Euler graph”.

The other question is more tricky: If the source of a cited piece of text contains an error in the grammar or spelling, or some other obvious error, should I correct it? First, you should try to reference the original source; it may be that the error was introduced in the secondary source that you first used. If so, quote the original source. If the original source has the error, then it is arguably appropriate to quote it verbatim but with “[sic]” appended. That is what I would do. However, there are different ideas about this. One is that peppering quoted text with “[sic]” is a slippery slope; just copy it as it stands. The other is simply to correct obvious mistakes without comment. That makes reading easier but offends the principle of historical precision. In the end, the decision is yours or the editor's, depending on who holds sway here.

(Added in edit) In this case, the original source (thanks to Gonçalo) is a reputable edited journal and bears the error. So some explanation is called for. My guess is that the author and/or editor thought that Euler was pronounced “yooler”, in analogy to eulogy, for which of course the form a eulogy is correct.

Answer 2

I'd use "an Euler graph". This is because the pronunciation of "Euler" begins with a vowel sound ("oi"), so "an" is preferred. Besides, Wikipedia and most other articles uses "an" too, so using "an" will be better for consistency. However, I don't think it really matters, as long as your readers can understand.

Answer 3

An is used before words that start with a vowel sound, and Euler is pronounced /ˈɔɪlər/, so there is no choice to be made.

When referencing something, though, you have to use the exact title.

Answer 4

Based on the comments, I think there is a strong case to quote it exactly, with no "[sic]". There appears to be a UK/US difference here. Normally you would not convert "colour" to "color" when citing a title, for instance (or vice versa). So, in the same way, this should be retained as a normal national language variation.

Answer 5

If you pronounce Euler as "You-ler", the answer is "A euler."

(Exactly as, for example, a yule log, or any other of the zillion Yi- words in English.)

If you pronounce Euler as "oo-ler", the answer is "An oo-ler."

The English language rule has nothing to do with starting with a vowel, it's about starting with a vowel sound.

Some points,

1. I have never ever ever heard You-ler prounced "oo-ler" "because of the German". Note for example that the word "volkswagen" is never, ever, ever pronounced "German -like" in English.

2. The a -> an transition in English has nothing to do with grammar, it's not a "grammar rule". It's a phonology issue: sandhi.

3. As everyone has pointed out, you don't "fix" regional spellings (but that's probably not an issue here, as it is "a yooler" everywhere).