Historical linguistics, also called diachronic linguistics, is the scientific study of how languages change over time. It aims to understand why languages change and how they have evolved over time. This field includes several important areas of study, such as rebuilding the languages that came before modern ones, grouping languages into families by comparing them (called comparative linguistics), and examining how culture and society influence language development.
This area of study is based on the uniformitarian principle, which means that the same language changes happening today likely happened in the past, unless there is strong evidence showing otherwise. Historical linguists work to describe and explain changes in specific languages, study the history of groups that speak those languages, and investigate the origins and meanings of words (known as etymology).
Development
Modern historical linguistics began in the late 18th century. It started from the earlier study of philology, which is the study of ancient texts and documents from long ago. At first, historical linguistics was the main part of comparative linguistics, which was used to rebuild early languages. Scholars focused on creating language families and rebuilding unrecorded early languages, using methods like comparison and analysis of language features. Early studies mostly focused on well-known Indo-European languages, many of which had long written histories. Scholars also studied the Uralic languages, another group of languages in Eurasia that had less early written material. Over time, comparative linguistics expanded to include languages outside Europe, such as Austronesian languages and many Native American language families. Comparative linguistics became one part of the larger field of historical linguistics. Today, studying Indo-European languages through comparison is a very specialized area of research.
Some scholars have tried to link different language families into larger groups, such as connecting Indo-European, Uralic, and others into Nostratic. These efforts have not been widely accepted. As time passes, it becomes harder to find evidence of language relationships. Methods used to study ancient languages have limits because similarities between words can happen by chance, and differences between language groups can make it hard to determine connections. Most experts believe that linguistic methods can reliably study languages up to about 10,000 years old. Several techniques are used to estimate the age of early languages, but the process is challenging, and results are usually approximate.
Diachronic and synchronic analysis
In the study of language, a synchronic analysis looks at language at a specific time, usually the present. It can also examine past language forms if needed. This is different from a diachronic analysis, which studies how language changes over time. Diachronic analysis is the main focus of historical linguistics. However, many other areas of linguistics study language as it is today, which is a type of synchronic analysis. Understanding how language changes helps explain how languages are represented now. All current language forms come from past changes, so explaining language structures requires looking at how they evolved over time.
At first, all modern linguistics focused on historical changes. Even the study of modern dialects involved looking at their past. Ferdinand de Saussure, a famous linguist, clearly separated synchronic and diachronic studies, which is still important today. Synchronic linguistics is considered more important, while diachronic linguistics studies how language changes step by step over time. Some people support Saussure’s ideas, while others disagree.
In practice, it is hard to study language exactly as it was spoken before the invention of the gramophone, because written records often do not show speech accurately. Before modern title pages were used, written records were hard to date correctly. Sometimes, historical clues like inscriptions or modern tools like carbon dating help determine dates. Also, sociolinguists have found that even within the same time period, people speak differently. For example, older and younger people may use language in ways that show it is changing. This means that language is always changing, even when studied at a single time.
Synchronic and diachronic methods can lead to different results. For example, the English verb "sing" has forms like "sang" and "sung," which seem irregular when studied at one time. However, from a historical perspective, these forms were once part of a regular system. Psycholinguistics, which studies how the brain processes language, and language teaching, both synchronic fields, show that irregular forms are learned differently than regular ones. Diachronic analysis, though, explains that these forms were once regular. Historical linguistics rarely uses the term "irregular verb."
The main tools used in diachronic linguistics are the comparative method and internal reconstruction. Some linguists use other methods, like mass lexical comparison, to compare many words across languages. However, most linguists think these methods are not reliable. Findings from historical linguistics help form ideas about how people and groups moved in the past, especially before written records existed. But it is often hard to connect language evidence with archaeological or genetic evidence. For example, there are many theories about where the Proto-Indo-Europeans lived and how they moved, but each theory explains the same archaeological evidence differently.
Comparative linguistics
Comparative linguistics, also called comparative language study, is a part of the study of how languages change over time. It focuses on comparing languages to find out if they share a common history. Languages can be connected in two ways: by borrowing words from each other or by having a shared origin. When languages share a common origin, they are called genetically related. Experts in this field group languages into families, rebuild early forms of languages, and study how languages have changed over time to explain differences seen in modern languages.
Etymology
Etymology is the study of how words develop over time. It looks at when words first appeared in a language, where they came from, and how their shapes and meanings have changed. Words can enter a language in different ways, such as being borrowed from another language as loanwords, being created by combining parts of existing words in the language, or through a method called phono-semantic matching, which blends sound and meaning elements.
In languages with long written histories, etymology uses philology, the study of how words change as cultures influence each other. Etymologists also use comparative linguistics, a method that helps scientists learn about very old languages with no written records. By comparing related languages, linguists can guess what their shared ancestor language might have been like and what words it had. This has allowed researchers to trace word roots back to the beginning of language groups, such as the Indo-European family. While etymology began in the field of philology, much of today’s research focuses on language families with little early documentation, like Uralic and Austronesian.
Dialectology
Dialectology is the study of language varieties, which are different ways people speak a language based mainly on where they live and the features of their speech. This is different from language changes caused by social factors, which are studied in sociolinguistics, or changes over time, which are studied in historical linguistics. Dialectology looks at topics like how two local dialects become different from a shared origin and how speech varies in the same time period.
Dialectologists focus on grammar rules that are common in certain areas. They often study people who have lived in the same place for many years without moving, as well as groups of people who move to new areas and bring their language with them. When people move to new places, they often bring their language practices, creating unique speech patterns in those communities. Dialectologists examine these speech patterns to learn how languages change and become different due to migration and cultural exchanges.
Phonology
Phonology is a part of linguistics that studies the sound system of a language or group of languages. While phonetics focuses on how speech sounds are physically made and heard, phonology looks at how sounds work within a language or across languages. Phonology examines whether sounds are treated as different or the same in a language. For example, the "p" in "pin" is aspirated, meaning it has a slight puff of air, while the "p" in "spin" is not. In English, these two sounds are used in specific situations and do not change the meaning of words, so they are called allophones of the same phoneme. In other languages, such as Thai and Quechua, the same difference in aspiration can change the meaning of words, so these sounds are considered separate phonemes. Phonology also studies how sounds change, like the /p/ in English, as well as topics such as syllable structure, stress, accent, and intonation.
The rules of phonology are also used to analyze sign languages, though the units studied are not sounds. Instead, they focus on visual elements like hand shapes or movements. These rules are general tools that work across different types of languages, not just specific ones.
Morphology and syntax
Morphology is the study of how words are formed in a language. It helps create rules that explain how speakers understand and use words. In historical linguistics, the way people express ideas changes over time. Words in a language's vocabulary are studied by lexicology. Along with clitics, words are usually considered the smallest parts of sentences. However, in most languages, words are connected by rules. These rules are known to speakers and show how word formation works during speech. In historical linguistics, the way people express ideas changes over time.
Syntax is the study of the rules and principles that help build sentences in natural languages. It focuses on the rules that shape sentence structure in specific languages. Researchers try to describe languages using these rules. Many historical linguists compare how sentences change in related languages or look for grammar rules that all natural languages follow, no matter when or where they are spoken.
Evolutionary context
Historical linguistics is the study of how languages change over time, similar to how Lamarckian ideas describe traits that can be passed down through generations. This field looks at how languages adjust in response to cultural, social, and environmental influences. In this view, language changes that happen during a person's life may affect how future speakers use the language.
Historical linguists use the terms "conservative" and "innovative" to describe how much a language changes compared to other similar languages. Conservative languages change more slowly over time, while innovative languages change more quickly.