Internal reconstruction in the context of "Linguistic reconstruction"

Proto-Armenian is the earlier, unattested stage of the Armenian language which has been reconstructed by linguists. As Armenian is the only known language of its branch of the Indo-European languages, the comparative method cannot be used to reconstruct its earlier stages. Instead, a combination of internal and external reconstruction, by reconstructions of Proto-Indo-European and other branches, has allowed linguists to piece together the earlier history of Armenian.

In linguistics, the comparative method is a technique for studying the development of languages by performing a feature-by-feature comparison of two or more languages with common descent from a shared ancestor and then extrapolating backwards to infer the properties of that ancestor. The comparative method may be contrasted with the method of internal reconstruction in which the internal development of a single language is inferred by the analysis of features within that language. Ordinarily, both methods are used together to reconstruct prehistoric phases of languages; to fill in gaps in the historical record of a language; to discover the development of phonological, morphological and other linguistic systems and to confirm or to refute hypothesised relationships between languages.

The comparative method emerged in the early 19th century with the birth of Indo-European studies, then took a definite scientific approach with the works of the Neogrammarians in the late 19th–early 20th century. Key contributions were made by the Danish scholars Rasmus Rask (1787–1832) and Karl Verner (1846–1896), and the German scholar Jacob Grimm (1785–1863). The first linguist to offer reconstructed forms from a proto-language was August Schleicher (1821–1868) in his Compendium der vergleichenden Grammatik der indogermanischen Sprachen, originally published in 1861. Here is Schleicher's explanation of why he offered reconstructed forms:

Linguistic reconstruction is the practice of establishing the features of an unattested ancestor language of one or more given languages. There are two kinds of reconstruction:

• Internal reconstruction uses irregularities in a single language to make inferences about an earlier stage of that language – that is, it is based on evidence from that language alone.
• Comparative reconstruction, usually referred to just as reconstruction, establishes features of the ancestor of two or more related languages, belonging to the same language family, by means of the comparative method. A language reconstructed in this way is often referred to as a proto-language (the common ancestor of all the languages in a given family).

Texts discussing linguistic reconstruction commonly preface reconstructed forms with an asterisk (*) to distinguish them from attested forms.

Old Japanese (上代日本語, Jōdai Nihon-go) is the oldest attested stage of the Japanese language, recorded in documents from the Nara period (8th century). It became Early Middle Japanese in the succeeding Heian period.Old Japanese is an early member of the Japonic language family. No genetic links to other language families have been proven.

The bulk of the Old Japanese corpus consists of poetry, especially the Man'yōshū, with a smaller number of formal prose works. These texts were written using man'yōgana, a writing system that employs Chinese characters as syllabograms or (occasionally) logograms. The language featured a few phonological differences from later forms, such as a simpler syllable structure and distinctions between several pairs of syllables that have been pronounced identically since Early Middle Japanese. The phonetic realization of these distinctions is uncertain. Internal reconstruction points to a pre-Old Japanese phase with fewer consonants and vowels.

Proto-Japonic, also known as Proto-Japanese or Proto-Japanese–Ryukyuan, is the reconstructed language ancestral to the Japonic language family. It has been reconstructed by using a combination of internal reconstruction from Old Japanese and by applying the comparative method to Old Japanese (both the central variety of the Nara area and Eastern Old Japanese dialects) and the Ryukyuan languages. The major reconstructions of the 20th century were produced by Samuel Elmo Martin and Shirō Hattori.