Outside the UK/USA people pronounce acronym EFI (Extensible Firmware Interface) in two different versions: [ɪfɪ] and [ɪ-ef-aɪ].

The first argue their pronunciation that 'I', for example, mean 'Interface' ([ˈɪntəfeɪs]) and should be read as [ɪ]. The second argue that the English letter 'I' is read as [aɪ].

From the point of native English speakers, what variant is more correct?

I hope there are some rules for it and this question is not opinion-based.

  • 1
    In response to your edit, I'm afraid there are no rules - or rather, no single set of rules - and it is rather a matter of opinion. I pronounce it like "effie", and UEFI is "you-effie", but that doesn't make me right or anything else wrong. In general, it's a case of either pronouncing it as if it were a word, or reading out the initials.
    – SamBC
    Commented Mar 24, 2019 at 23:12
  • 2
    Firstly, Wikipedia isn't reliable on subjects that are matters of dispute; it has a tendency to be subject to slow edit wars that don't generate enough attention to lead to protection, or the community takes a side for no good reason. Secondly, it lists both pronunciations of SQL that I just gave.
    – SamBC
    Commented Mar 24, 2019 at 23:20
  • 2
    If other members of the room look at you with strange faces, than you are probably pronouncing it the wrong way within your community. See the proverb When in Rome....
    – J.R.
    Commented Mar 25, 2019 at 11:21
  • 3
    Do note that /ɪ/ and /i:/ are not the same thing. The letter E is pronounced /i:/, so the initialism EFI would be pronounced /ˌi: ef ˈaɪ/. If you pronounce EFI as a word, rather than as individual letters, I think you'd end up with /ˌi:fi/. Regardless, I think you've gotten your point across.
    – user3395
    Commented Mar 25, 2019 at 14:23
  • 1
    @SamBC I usually have to piece my IPA together by stealing bits from dictionary definitions and piecing them together, which is why I linked that tool :) I think it’s easy to assume it’s obvious how to pronounce words that seem common to us, but English has both regional differences in pronunciation and spellings irregularities that make it hard to guess an intended pronunciation of an unfamiliar word. It’s not a big deal in this context, but I wanted to mention it because not attempting to use a phonetic transcription has caused confusion in the past.
    – ColleenV
    Commented Mar 25, 2019 at 14:57

1 Answer 1


Whether or not an acronym has a "correct variant" is largely dependent on how often it's used in everyday language. EFI, like many computer-related acronyms, has no widely accepted pronunciation because it is only regularly used by a small number of people. Some people pronounce each individual letter (like I do) and others have their own preferred pronunciation.

Unfortunately I think you have to accept that you and your boss are going to have different opinions about how to pronounce it, because neither of you are wrong. Maybe you can make it into a joke between the two of you?

  • We had two pronunciations in our office for LIFFE. One group pronounced it /'laɪf/ and some pronounced it /lɪ'fi/ (it's too long for most people to spell out though). No-one cared and everyone understood each other. If your boss insists on a particular pronunciation though, it's probably best to just go with that version and let the matter drop.
    – ColleenV
    Commented Mar 25, 2019 at 13:06
  • Thank you very much for your answer. I think I need to make it little clear: we have a Russian-speaking office and therefore the pronunciation of any English term is strongly evident. Also, non-English speakers find it harder to understand English words even with minimal deviations from the pronunciation they expect to hear. When we have disagreements about this, usually someone finds a source of information about the correct pronunciation and then everyone comes to a common variant. But in the case of EFI such information was not found, so I asked a question. Commented Mar 25, 2019 at 13:53

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