As peculiar as it may seem, the studies of linguistics and epidemiology intersect in more ways than we might think. Broadly speaking, epidemiology is the study of how diseases or illnesses can spread throughout populations. On the other hand, linguistics is the study of language, encompassing the examination of specific languages and general language characteristics. 

When studying linguistics in epidemiological terms, linguists contend that people do not transmit entire languages to each other through a single event, but instead in small units over time known as linguistic items. Hence, in linguistic epidemiology, the focus is on tracking how these small linguistic items spread through populations as individuals are exposed to them, creating chains of transmission.

Variation and transmission

People can understand the epidemiology of linguistic items through the distribution of linguistic variants: two or more alternative forms of a single linguistic item. An example of a linguistic item is morphemes, the smallest grammatical unit of speech. Morphemes can be entire words or small fragments of words, like a suffix.

One of the most researched linguistic variants in the English language is that of the “-ing” variable. There is variation in “-ing” because some speakers pronounce words like “driving” with a velar pronunciation [ŋ] — as in, with the back of their tongue touching the back of their upper mouth. Others use an alveolar/apical [n] pronunciation — as in, with the tip of their tongue touching the ridge behind their front teeth — to create a form that roughly sounds like “drivin.”

Speakers can spread the linguistic variants through daily interactions with other people, where individual speakers adopt and pass on specific variants, and through relocation, where groups moving to a new area bring two dialects into closer interaction. Linguists can study the transmission of variants of linguistic items present in dialects across populations using epidemiological methods.

Adopting epidemiological methods

In his book Linguistic Epidemiology, linguist Nick J. Enfield argues that the type of linguistic variants that spread depends on the behaviour of their carriers. According to Enfield, an individual has to reproduce the linguistic item in some way, by pronouncing or repeating a word, to expose more individuals to that item. However, the behavioural pattern of how individuals reproduce that item varies, giving rise to variants. As such, the type of linguistic variant that a person adopts depends on the variant that they were exposed to. 

Enfield suggests that we can use epidemiological approaches to understand how linguistic variants spread among a population. This involves using social networks, and accounting for social and cognitive factors, to understand the potential transmissibility of given variants.

The ‘social network model’ proposes that speakers are nodes within a social network where each speaker is linked to others through communication. This network could also include sources such as advertising, written materials, television, and radio as nodes in the network model. In essence, we analyze an individual’s network of connections to pinpoint the origins of novel linguistic behaviours and identify the individuals or sources shaping their speech.

Beyond locating sources of linguistic forms, linguists may also study an individual person’s potential to transmit linguistic forms — in the same way an epidemiologist may seek to study the potential of an individual to transmit a virus. 

To study an individual’s potential to spread a new facet of language, linguistic epidemiology takes into account cognitive and social factors. When considering social factors, for example, it is important to acknowledge that the specific linguistic variant that a person adopts is influenced by their desire to sound like a member of a specific social group. Linguistic expressions, then, are socially marked, conveying both semantic and social meaning.

So, next time you hear someone using another linguistic twist, blame it on linguistic epidemiology — making language infectious, one conversation at a time!