I hear that native (american, but maybe others do too) English speakers sometimes change the sound /n/ for a /m/ in between words like "Conversation" and "Grandpa". Is there a rule or explanation for it? I was thinking that maybe it happens when /n/ comes after some vowels?
Conversation has no M sound. Grampa is what a kid can say, as the N sound is unnatural in a complex word until maybe second grade (See aminal.)– Yosef BaskinDec 28, 2022 at 19:13
3@YosefBaskin — Does anyone of any age ever say grand-pa or grand-ma? It's always gram-pa and gram-ma in these parts.– Tinfoil HatDec 28, 2022 at 19:16
The point of articulation of the N and M are very close together. Say man, then say nan. The n one is harder. It's no secret that babies can say mama before they can say nana. The n requires one to lift the whole jaw up so the tongue almost touches the alveolar ridge....'nough said. And this has zero to do with American accents.– LambieDec 28, 2022 at 19:28
@TinfoilHat - I say gran-pa and gran-ma.– Kate BuntingDec 29, 2022 at 9:06
It is based on the following consonant.
When /n/ is followed by a consonant pronounced with the lips (in linguistics terms, a "labial" consonant), the /n/ can change to sound more like /m/, which is itself a labial consonant.
This change can be described as an example of either “gestural overlap” or “assimilation”. It is generally optional, but it is probably more common than not in the specific word "grandpa".
Bilabial consonants (pronounced with both lips) include /p/, /b/ and /m/.
The consonants /f/ and /v/ are "labiodental": pronounced with the lower lip against the upper teeth. Before these, assimilation/gestural overlap results in a consonant that is transcribed in the International Phonetic Alphabet as [ɱ]: a labiodental nasal. This may sound like /m/, since it is also a possible pronunciation of /m/ before /f/ or /v/ (e.g. in "symphony" or "nymph"), but there is a phonetic difference between [m] and [ɱ].
It looks like a duplicate of those “related” questions. Dec 28, 2022 at 19:22
Grandpa often becomes Grampa, and d is not bilabial. It's due to the nd being more difficult than an mp.– LambieDec 28, 2022 at 21:05
It’s very smart of you to notice this. Most English speakers do it without thinking. The realization ⟨n⟩ with a labial sound ([m] or sometimes [ɱ]) is actually related to the surrounding consonants and not the vowels.
Before /p/ and /b/, it is easier to say [m] rather than [n] because [p], [b], and [m] are all bilabial sounds. Many speakers do this, but it is not required.
The situation is a bit more complicated when ⟨n⟩ appears before /f/ and /v/. [n], [m], and [ɱ] (a labiodental nasal) are all possible. Some speakers also pronounce /m/ as [ɱ] before /f/ and /v/ because all three are labiodental sounds. Sometimes, it is even possible to skip the nasal consonant all together as long as the preceding vowel is nasalized. For example, I might pronounce “conversation” as [ˌkʰɑ̟̃.vɹ̩̈.ˈse̞i̯.ʃə̆n] in informal contexts. If you’re a learner, you don’t really need to worry about this.
This type of regressive assimilation occurs in many languages all over the world. For one, it's just like in Spanish, where “nasals assimilate to the place of articulation of the following consonant... Thus /n/ is realized as [m] before labial consonants, and as [ŋ] before velar ones“ per Wikipedia. So invierno, which is their word for winter, has only an [m] at the start of the word before written "v": [imˈbjeɾno]. And they do the same in banco as we do in bank: make it an [ŋ] there before the [k].– tchrist ♦Dec 28, 2022 at 20:03
How can Mama versus Nene not be about the vowel sounds? Those are initial sounds...Also, /n/ has a more complicated point of articulation than /m/, so it's natural for grandpa to become grampa.– LambieDec 28, 2022 at 20:59