The Neogrammarians (also Young Grammarians, German Junggrammatiker) were a German school of linguists, originally at the University of Leipzig, in the late 19th century who proposed the Neogrammarian hypothesis of the regularity of sound change. According to this hypothesis, a diachronic sound change affects simultaneously all words in which its environment is met, without exception. Verner's law is a famous example of the Neogrammarian hypothesis, as it resolved an apparent exception to Grimm's law. Today this hypothesis is considered more of a guiding principle than an exceptionless fact, as numerous examples of lexical diffusion (where a sound change affects only a few words at first and then gradually spreads to other words) have been attested. Broadly conceived, linguistics is the scientific study of human language, and a linguist is someone who engages in this study. ... The University of Leipzig (Universität Leipzig), located in Leipzig in the Free State and former Kingdom of Saxony, is one of the oldest universities in Europe. ... Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... Sound change or phonetic change is a historical process of language change consisting in the replacement of one speech sound or, more generally, one phonetic feature by another in a given phonological environment. ... Historical linguistics (also diachronic linguistics or comparative linguistics) is primarily the study of the ways in which languages change over time, by means of examining languages which are recognizably related through similarities such as vocabulary, word formation, and syntax, as well as the surviving records of ancient languages. ... Verners law, stated by Karl Verner in 1875, describes a historical sound change in the Proto-Germanic language whereby voiceless fricatives *f, *þ, *s and *x, when immediately following an unstressed syllable in the same word, underwent voicing and became respectively *b, *d, *z and *g. ... Grimms law (also known as the [First] Germanic Sound Shift; German: Erste Deutsche (Germanische) Lautverschiebung) was the first non-trivial systematic sound change ever to be discovered; its formulation was a turning-point in the development of linguistics, enabling the introduction of rigorous methodology in historical linguistic research. ... Lexical diffusion is the theory that sound change originates in a single word or a small group of words and then spreads by analogy to other words with a similar phonological make-up, but may not spread to all words in which it potentially could apply. ...

Other contributions of the Neogrammarians to general linguistics were:

• The object of linguistic investigation is not the language system, but rather the idiolect, that is, language as it is localized in the individual, and therefore is directly observable.
• Autonomy of the sound level: being the most observable aspect of language, the sound level is seen as the most important level of description, and absolute autonomy of the sound level from syntax and semantics is assumed.
• Historicism: the chief goal of linguistic investigation is the description of the historical change of a language.
• Analogy: wherever the premise of the inviolability of sound laws fails, analogy is applied as an explanation. Thus, exceptions are understood to be a (regular) adaptation to a related form.

Leading Neogrammarian linguists included: An idiolect (sometimes misspelled ideolect) is a variety of a language unique to an individual. ... Language change is the manner in which the phonetic, morphological, semantic, syntactic, and other features of a language are modified over time, it is the topic addressed by historical linguistics which looks at the past states of a language and seek to explain how the present state came about. ... An analogy is a comparison between two different things, in order to highlight some form of similarity. ...

• Wilhelm Braune
• Karl Brugmann
• Berthold Delbrück
• August Leskien
• Hermann Osthoff
• Hermann Paul
• Eduard Sievers
• Karl Verner
• August Leskien
• Otto Behaghel

Despite their strong influence in their time, the methods and goals of the Neogrammarians have been criticized from various points of view, but mainly for: reducing the object of investigation to the idiolect; restricting themselves to the description of surface phenomena (sound level); overvaluation of historical languages and neglect of contemporary ones. Karl Brugmann was a German linguist (1849-1919) and one of the leading figures in Indo-European languages research. ... A German linguist (1942-1922) who devoted himself to the study of the comparative syntax of the Indo-European languages. ... Karl Adolf Verner (* 7. ...