/n/ to /m/ rule?

[5jj]

It seems to me that a phonetic rule for one word is not particularly helpful. /n/ is the pronunciation in all the other words I can think of with /f/ following a post-vocalic /n/.

I wrote those words in another thread in response to one of lauralie2’s posts:

Allophones are predictable: they occur in obvious phonetic environments. For example, Banff (place in Canada) has two pronunciations, Ba[n]ff and Ba[m]ff. If you were a linguist hearing this language for the first time, how would you write down the word, with an <n> or an <m>? That is, which phoneme would you choose, /n/ or /m/? The answer is in the phonetic environment, predictability: both [m] and [f] are pronounced with the lips. The two sounds [m] and [f] share articulatory features. That's the 'obvious phonetic environment' I mentioned above. The word is Banff, with an /n/. The phonetic rule: /n/ is pronounced as [m] before /f/ in the word <Banff>.

Since then, I have looked up Banff in John Wells’s Longman Pronunciation Dictionary (3rd edition, 2008). He gives the pronunciation for both BrE and AmE as /n/ (with a superscript /t/, with /m/ (with a superscript /p/) as a variant. He uses a symbol to denote that the variant is ‘derived by rule’.

I still don’t think that a phonetic rule for one word is helpful. Can anybody come up with any other inf words in which the /n/ is pronounced /m/? Or is there something else that I am missing?

[raindoctor]

information (imf); s and p (smp)

[Raymott]

I still don’t think that a phonetic rule for one word is helpful. Can anybody come up with any other inf words in which the /n/ is pronounced /m/? Or is there something else that I am missing?

I agree, but it's not just for one word.
'Information' can be pronounced 'imf...' (perhaps influenced by anticipation of the /m/)

But this also applies to the bilabials, /p/ and /b/
Here are some examples. I won't worry about IPA, since it's the n/m distinction that's being made (and I'm not saying everyone makes this switch):
input -> /imput/; inpatient
Canberra -> /Camberra/; Cranberry -> cramberry; in between; in books;

You might be missing that Banff is a proper name, and if the original Mr or Mrs Banff said it was Bamff, or Bampff, then that's what it is.
This intrusive /p/ can also occur in /compfortable/ and similar words.

Learners: the above are not recommendations.

PS: Oops, I note "information" has been given. Er ... "informal"