Over the holidays I was mercilessly teased for my diphthongs. Before you imagine something far worse than necessary, let me clarify that a diphthong is a combination of vowel sounds spoken in one syllable—think the “ah-oo” in “cow.” Minnesota where I was raised, monophthongs predominate, particularly the “long o.” A Minnesotan says boat as “b-oh-t,” where many others would use a diphthong “b-oh-oo-t.”
Only four years after trading Minnesota’s mosquitos for Montana’s mountains, diphthongs have weaseled their way into my speech, much to the amusement of my friends and family. My brother mistakenly characterized my new accent as“twang.” My best friend was closer, saying, “You’re adding extra sounds now.”
As with most areas of speech and language, how and why people acquire a second dialect in their native language is a multifactorial process involving linguistic, social, and developmental factors that the speaker may not even be aware of.*
Human beings are masters at getting what we want, when we want it. If someone with a strong accent has to repeat themselves to be understood, they may change their accent out of sheer frustration. In my case, I was perfectly intelligible to people in Montana (though many initially thought I was Canadian), so my accept convergence resulted from other factors.
It is easier for young children to learn a second language, or second dialect, than for adults. One study found that white women who befriended speakers of African American Vernacular English (AAVE) at younger ages acquired more speech characteristics of AAVE than those who befriended them when they were older.
However, this does not mean adults are incapable of changing their accents. Another study found that adult Canadians living in New York began to differentiate between the vowels in cot and caught, which would be pronounced identically in Canadian (as well as Minnesotan) English. A third study of Canadians in Alabama found similar findings. Remarkably, you do not have to be a speech-language pathologist or linguist to hear these differences. Just as my brother and friend noticed my use of diphthongs, untrained listeners were able to rate the American-ness in the Canadians’ speech.
People are more likely to change their accents if the new accent is considered more prestigious. For example, a person who speaks Appalachian English may useStandard English in the workplace. Another example is newscasters adopting a more standard variety of English to reach a broader audience.
Generally speaking, women tend to be more linguistically innovative than men. If you want to know what people will sound like in the future, listen to teenage girls. Women also tend to more readily acquire prestige dialects, while men may stick with working-class speech. That being said, as gender roles in society continue to change, this tendency may change as well.
Social Connection and Social Distance
Another reason people change their accents is to be accepted into a social group or to emulate someone whom they admire. Simply put, if I like you, I am more prone to talk like you, and if I talk like you, you are more apt to like me. The reverse is also true. If I don’t like you, I will try to distance myself from you by the way I speak.
This phenomenon extends even to the topic of conversation. When speaking of something related to the first dialect, a hometown, for example, the speaker will be more likely to use that dialect if they have positive feelings toward it. If the speaker hated their hometown, however, they may be more apt to use their second dialect when speaking about it.
As society continues to become more mobile, we are likely to see an increase in the number of bi-dialectal speakers. Acquiring a second dialect is a natural, though complex, process, so when one of your friends or relatives returns from a trip abroad with a bit of “twang,” try not to make fun of them too much.
*Note: I have used the terms accent and dialect relatively interchangeably in this post, but they are different. An accent refers strictly to speech sounds, while a dialect is an entire language variation. For example, Minnesotans refer to sugary, carbonated soft drinks as pop, while someone from the South may refer to them as cokes. This is a dialectal variation that has nothing to do with accent.
 Fix, Sonya. “Age of Second Dialect Acquisition and Linguistic Practice Across Ethno-Racial Boundaries in the Urban Midwest,” n.d.,12.
 Nycz, Jennifer. “NewContrast Acquisition: Methodological Issues and Theoretical Implications.” English Language and Linguistics, Phonological Mergers in English, 17, no. 2(2013): 325–57. https://doi.org/10.1017/S1360674313000051.
  Munro, Murray J, Tracey MDerwing, and James E Flege. “Canadians in Alabama: A Perceptual Study ofDialect Acquisition in Adults.” Journal of Phonetics 27, no. 4 (October1999): 385–403. https://doi.org/10.1006/jpho.1999.0101.
 Trudgill, Peter. “Sex, Covert Prestige and Linguistic Change in the Urban British English of Norwich.”Language in Society 1 (October 1, 1972): 179–95.https://doi.org/10.1017/S0047404500000488.
 Nycz, Jennifer. “ChangingWords or Changing Rules? Second Dialect Acquisition and Phonological Representation.” Journal of Pragmatics 52 (2013): 49–62.https://doi.org/10.1016/j.pragma.2012.12.014.
 Nosowitz, Dan. “We Asked a Linguist to Explain the ‘Semester Abroad Accent.’” Atlas Obscura, 29:00 500.http://www.atlasobscura.com/articles/are-semester-abroad-accents-real-or-fake.