Language change

Language change is the phenomenon whereby phonetic, morphological, semantic, syntactic, and other features of language vary over time. The effect on language over time is known as diachronic change. Two linguistic disciplines in particular concern themselves with studying language change: historical linguistics and sociolinguistics. Historical linguists examine how people in the past used language and seek to determine how subsequent languages derive from previous ones and relate to one another. Sociolinguists study the origins of language changes and want to explain how society and changes in society influence language.

Causes of language change

 * 1) economy: Speakers tend to make their utterances as efficient and effective as possible to reach communicative goals.  Purposeful speaking therefore involves a trade-off of costs and benefits.
 * 2) * the principle of least effort: Speakers especially use economy in their articulation, which tends to result in phonetic reduction of speech forms. See vowel reduction, cluster reduction, lenition, and elision. After some time a change may become widely accepted (it becomes a regular sound change) and may end up treated as a standard. For instance: going to → gonna, with examples of both vowel reduction  and elision ,.
 * 3) analogy - reducing word forms by likening different forms of the word to the root.
 * 4) language contact - the borrowing of words from foreign languages.
 * 5) the medium of communication
 * 6) cultural environment: Groups of speakers will reflect new places, situations, and objects in their language, whether they encounter different people there or not.

Rudi Keller discusses language change in the context of evolutionary process: "the historical evolution of language", proposing his invisible hand explanation.

Types of language change
All languages change constantly, and do so in many and varied ways. Each generation notes how other generations "talk funny".

Marcel Cohen details various types of language change under the overall headings of the external evolution and internal evolution of languages.

Lexical changes
The study of lexical changes forms the diachronic portion of the science of onomasiology.

The ongoing influx of new words in the English language (for example) helps make it a rich field for investigation into language change, despite the difficulty of defining precisely and accurately the vocabulary available to speakers of English. Throughout its history English has not only borrowed words from other languages but has re-combined and recycled them to create new meanings, whilst losing some old words.

Dictionary-writers try to keep track of the changes in languages by recording (and, ideally, dating) the appearance in a language of new words, or of new usages for existing words. By the same token, they may tag some words as "archaic" or "obsolete".

Phonetic and phonological changes
The concept of sound change covers both phonetic and phonological developments.

The sociolinguist William Labov recorded the change in pronunciation in a relatively short period in the American resort of Martha’s Vineyard and showed how this resulted from social tensions and processes. Even in the relatively short time that broadcast media have recorded their work, one can observe the difference between the pronunciation of the newsreaders of the 1940s and the 1950s and the pronunciation of today. The greater acceptance and fashionability of regional accents in media may also reflect a more democratic, less formal society — compare the widespread adoption of language policies.

The mapping and recording of small-scale phonological changes poses difficulties, especially as the practical technology of sound recording dates only from the 19th century. Written texts provide the main (indirect) evidence of how language sounds have changed over the centuries. But note Ferdinand de Saussure's work on postulating the existence and disappearance of laryngeals in Proto-Indo-European as an example of other methods of detecting/reconstructing sound-changes within historical linguistics.

Spelling changes
Standardisation of spelling originated relatively recently. Differences in spelling often catch the eye of a reader of a text from a previous century. The pre-print era had fewer literate people: languages lacked fixed systems of orthography, and the handwritten manuscripts that survive often show words spelled according to regional pronunciation and to personal preference.

Semantic changes
Semantic changes include
 * pejoration, in which a term acquires a negative association
 * amelioration, in which a term acquires a positive association
 * widening, in which a term acquires a broader meaning
 * narrowing, in which a term acquires a narrower meaning

Sociolinguistics and language change
The sociolinguist Jennifer Coates, following William Labov, describes linguistic change as occurring in the context of linguistic heterogeneity. She explains that “[l]inguistic change can be said to have taken place when a new linguistic form, used by some sub-group within a speech community, is adopted by other members of that community and accepted as the norm.”

Can and Patton (2010) provide a quantitative analysis of twentieth century Turkish literature using forty novels of forty authors. Using weighted least squares regression and a sliding window approach they show that as time passes, words, both in terms of tokens (in text) and types (in vocabulary), have become longer. They indicate that the increase in word lengths with time can be attributed to the government-initiated language “reform” of the 20th century. This reform aimed at replacing foreign words used in Turkish, especially Arabic- and Persian-based words (since they were in majority when the reform was initiated in early 1930s), with newly coined pure Turkish neologisms created by adding suffixes to Turkish word stems (Lewis, 1999).

Can and Patton (2010), based on their observations of the change of a specific word use (more specifically in newer works the preference of “ama” over “fakat”, where both are borrowed from Arabic and mean “but” in English, and their inverse usage correlation is statistically significant), also speculate that the word length increase can influence the common word choice preferences of authors.

Quantifying language change
Altintas, Can, and Patton (2007) introduce a systematic approach to language change quantification by studying unconsciously-used language features in time-separated parallel translations. For this purpose, they use objective style markers such as vocabulary richness and lengths of words, word stems and suffixes, and employ statistical methods to measure their changes over time.