Around 2.4 million people have at least some degree of competence in the language, mainly in Galicia, an autonomous community located in northwestern Spain, where it has official status along with Spanish.

The language is also spoken in some border zones of the neighbouring Spanish regions of Asturias and Castile and León, as well as by Galician migrant communities in the rest of Spain, in Latin America including Argentina, Uruguay, Puerto Rico, the United States, Switzerland and elsewhere in Europe.

The earliest document written integrally in the local Galician variety dates back to 1230, although the subjacent Romance permeates most written Latin local charters since the High Middle Ages, being specially noteworthy in personal and place names recorded in those documents, as well as in terms originated in languages other than Latin.

[1] The current linguistic status of Galician with regard to Portuguese is controversial in Galicia, and the issue sometimes carries political overtones.

[16] With regard to the external and internal perception of this relation, for instance in past editions of the Encyclopædia Britannica, Galician was defined as a "Portuguese dialect" spoken in northwestern Spain.

On the other hand, the director of the Instituto Camões declared in 2019 that Galician and Portuguese were close kin, but different languages.

Portuguese Early Modern Era grammars and scholars, at least since Duarte Nunes de Leão in 1606, considered Portuguese and Galician two different languages[21] derived from old Galician, understood as the language spoken in the Northwest before the establishment of the Kingdom of Portugal in the 12th century.

The surge of the two languages would be the result of both the elaboration of Portuguese, through the royal court, its internationalization and its study and culture;[22] and of the stagnation of Galician.

[5] In Spanish "lenguaje gallego" is already documented in this same century, circa 1330;[25] in Occitan circa 1290, in the Regles de Trobar by Catalan author Jofre de Foixà: "si tu vols far un cantar en frances, no·s tayn que·y mescles proençal ne cicilia ne gallego ne altre lengatge que sia strayn a aquell" [If you want to compose a song in French, you should not admix Provençal nor Sicilian nor Galician nor other language which is different from it].

In 2014, the parliament of Galicia unanimously approved Law 1/2014 regarding the promotion of the Portuguese language and links with the Lusophony.

[31] Galician is spoken by some three million people,[citation needed] including most of the population of Galicia and the numerous Galician communities established elsewhere, in Spain (Madrid, Barcelona, Biscay), in other European cities (Andorra la Vella, Geneva, London, Paris), and in the Americas (New York, New Jersey, Buenos Aires, Córdoba/Argentina, Montevideo, Mexico City, Havana, Caracas, San Juan in Puerto Rico, São Paulo, Managua, Mayagüez, Ponce, Panama City).

The first non-literary documents in Galician-Portuguese date from the early 13th century, the Noticia de Torto (1211) and the Testamento of Afonso II of Portugal (1214), both samples of medieval notarial prose.

Not only the kings but also the noble houses of Galicia and Portugal encouraged literary creation in Galician-Portuguese, as being an author or bringing reputed troubadours into one's home became a way of promoting social prestige.

As a result, many noblemen, businessmen and clergymen of the 13th and 14th centuries became notable authors, such as Paio Gomes Charinho, lord of Rianxo, and the aforementioned kings.

Aside from the lyric genres, Galicia developed also a minor tradition on literary prose, most notably in translation of European popular series, as those dealing with King Arthur written by Chrétien de Troyes, or those based on the war of Troy, usually paid and commissioned by noblemen who desired to read those romances in their own language.

As for other written uses of Galician, legal charters (last wills, hirings, sales, constitutional charters, city council book of acts, guild constitutions, books of possessions, and any type of public or private contracts and inventories) written in Galicia are to be found from 1230 to 1530—the earliest one probably a document from the monastery of Melón, dated in 1231[43]—being Galician by far the most used language during the 13th, 14th and 15th centuries, in substitution of Latin.

[44] Also, from 1480 on, notaries of the Crown of Castile were required to obtain their licenses in Toledo, where they had to prove their mastery of Spanish.

[44] In spite of Galician being the most spoken language, during the 17th century, the elites of the Kingdom began speaking Spanish, most notably in towns and cities.

Other important sources are a number of sonnets and other lyric poetry, as well as other literate productions, including the forgery of allegedly mediaeval scriptures or chronicles under diverse pretensions—usually to show the ancient nobility of the forger's family—being these writings elaborated in an archaic looking Galician which nevertheless could not conceal the state of the language during this period.

Middle Galician is characterized by a series of phonetic processes which led to a further separation from Portuguese, and to the apparition of some of the more noteworthy dialectal features, among other phenomenons: emergence of the gheada or pronunciation of /ɡ/ as a pharyngeal fricative; denasalization of nasal vowels in most of Galicia, becoming oral vowels in the east, or a group formed by an oral vowel plus a nasal consonant in the west; reduction of the sibilant system, with the confluence (except in the Baixa Limia region) of voiced and voiceless fricatives, followed by a process of de-affrication which led to different results in the west and in the east.

His Elementos etimológicos segun el método de Euclides (1766), written in Spanish but dealing with Galician, was in fact one of the first comprehensive studies on sound change and evolution of any European language.

[50] It was headed by three main authors: Rosalia de Castro, an intimist poet; Eduardo Pondal, of nationalist ideology, who championed a Celtic revival; and Manuel Curros Enríquez, a liberal and anticlerical author whose ideas and proclamations were scandalous for part of the 19th-century society.

An important landmark was the establishment of the Royal Galician Academy, in 1906, soon followed by that of the Seminario de Estudos Galegos (1923).

Following the victory of Francisco Franco in the Spanish Civil War, the written or public use of the Galician language was outlawed.

[52] Galician is taught in schools, and there is a public Galician-language television channel, Televisión de Galicia.

Galician allows pronominal clitics to be attached to indicative and subjunctive forms, as does Portuguese, unlike modern Spanish.

In July 2003, the Royal Galician Academy modified the language normative to admit and promote some archaic Galician-Portuguese forms conserved in modern Portuguese, merging the NOMIG and the main proposals of the moderate sectors of reintegrationism; the resulting orthography is used by the vast majority of media, cultural production and virtually all official matters including education.

The syllable receiving the primary stress can generally be identified by the spelling of the word according to the language's rules of orthography.