Irish (Standard Irish: ), also known as Irish Gaelic () or (primarily outside Ireland) simply Gaelic ( ), is a Celtic language within the Indo-European language family native to the Irish people and indigenous to the island of Ireland. It was the first language of the majority of the population until the 19th century, when English gradually became dominant, particularly in the last decades of the century.

Today, Irish is still commonly spoken as a first language in Ireland's Gaeltacht regions, in which 2% of Ireland's population lived in 2022.

The total number of people (aged 3 and over) in Ireland who declared they could speak Irish in April 2022 was 1,873,997, representing 40% of respondents, but of these, 472,887 said they never spoke it and a further 551,993 said they only spoke it within the education system. Linguistic analyses of Irish speakers are therefore based primarily on the number of daily users in Ireland outside the education system, which in 2022 was 20,261 in the Gaeltacht and 51,707 outside it, totalling 71,968. In the 2021 census of Northern Ireland, 43,557 individuals stated they spoke Irish on a daily basis, 26,286 spoke it on a weekly basis, 47,153 spoke it less often than weekly, and 9,758 said they could speak Irish, but never spoke it. From 2006 to 2008, over 22,000 Irish Americans reported speaking Irish as their first language at home, with several times that number claiming "some knowledge" of the language.

For most of recorded Irish history, Irish was the dominant language of the Irish people, who took it with them to other regions, such as Scotland and the Isle of Man, where Middle Irish gave rise to Scottish Gaelic and Manx. It was also, for a period, spoken widely across Canada, with an estimated 200,000–250,000 daily Canadian speakers of Irish in 1890. On the island of Newfoundland, a unique dialect of Irish developed before falling out of use in the early 20th century.

With a writing system, Ogham, dating back to at least the 4th century AD, which was gradually replaced by Latin script since the 5th century AD, Irish has one of the oldest vernacular literatures in Western Europe. On the island, the language has three major dialects: Connacht, Munster, and Ulster Irish. All three have distinctions in their speech and orthography. There is also , a standardised written form devised by a parliamentary commission in the 1950s. The traditional Irish alphabet, a variant of the Latin alphabet with 18 letters, has been succeeded by the standard Latin alphabet (albeit with 7–8 letters used primarily in loanwords).

Irish has constitutional status as the national and first official language of the Republic of Ireland, and is also an official language of Northern Ireland and among the official languages of the European Union. The public body Foras na Gaeilge is responsible for the promotion of the language throughout the island. Irish has no regulatory body but , the standard written form, is guided by a parliamentary service and new vocabulary by a voluntary committee with university input.

Name of the language In Irish

In ("The Official [Written] Standard") the name of the language is , from the south Connacht form, spelled prior the spelling reform of 1948, in which the silent was removed. was originally the genitive of , the form used in Classical Gaelic. Older spellings include in Classical Gaelic and in Old Irish. Goidelic, used to refer to the language family, is derived from the Old Irish term.

Endonyms of the language in the various modern Irish dialects include: in Galway, // in Mayo and Ulster, / in West Cork and Kerry (Munster), as well as in mid- and eastern Munster (Waterford and parts of Cork and Kerry), to reflect local pronunciation.

as a term can apply to the very closely related languages Scottish Gaelic and Manx as well as Irish. When context requires it, these three are distinguished as , and respectively.

In English In English (including Hiberno-English), the language is usually referred to as Irish, as well as Gaelic and Irish Gaelic. An example of the use of the word "Gaelic" to describe the language, seen throughout the text of the article. The term Irish Gaelic may be seen when English speakers discuss the relationship between the three Goidelic languages (Irish, Scottish Gaelic and Manx). Gaelic is a collective term for the Goidelic languages, and when the context is clear it may be used without qualification to refer to each language individually. When the context is specific but unclear, the term may be qualified, as Irish Gaelic, Scottish Gaelic or Manx Gaelic. Historically the name "Erse" ( ) was also sometimes used in Scots and then in English to refer to Irish; as well as Scottish Gaelic.

History

Primitive Irish

Written Irish is first attested in inscriptions from the 4th century AD, a stage of the language known as Primitive Irish. These writings have been found throughout Ireland and the west coast of Great Britain.

Old Irish

Primitive Irish underwent a change into Old Irish through the 5th century. Old Irish, dating from the 6th century, used the Latin alphabet and is attested primarily in marginalia to Latin manuscripts. During this time, the Irish language absorbed some Latin words, some via Old Welsh, including ecclesiastical terms: examples are (bishop) from , and (Sunday, from ).

Middle Irish

By the 10th century, Old Irish had evolved into Middle Irish, which was spoken throughout Ireland, the Isle of Man and parts of Scotland. It is the language of a large corpus of literature, including the Ulster Cycle. From the 12th century, Middle Irish began to evolve into modern Irish in Ireland, Scottish Gaelic in Scotland, and Manx on the Isle of Man.

Early Modern Irish

Early Modern Irish, dating from the 13th century, was the basis of the literary language of both Ireland and Gaelic-speaking Scotland.

Modern Irish Modern Irish, sometimes called Late Modern Irish, as attested in the work of such writers as Geoffrey Keating, is said to date from the 17th century, and was the medium of popular literature from that time on.

Decline By the late 18th century, the language lost ground in the east of the country. The reasons behind this shift were complex but came down to a number of factors: Discouragement of its use by the Anglo-Irish administration. The Catholic Church's support of English over Irish. The spread of bilingualism from the 1750s onwards.

The decline of the Irish language from the late 17th century onwards can be understood through diglossia and transitional bilingualism, marked by monoglot Irish-speaking grandparents, bilingual children, and monoglot English-speaking grandchildren. Despite the first printed book in Irish in 1685 and the introduction of the printing press, demand for Irish-language literature remained low due to the dominant influence of English and the socioeconomic conditions of the Anglo-Irish ruling class, the Protestant Ascendancy. This resulted in the publishing industry focusing primarily on English-language materials, marginalizing Irish-language publications.

During the conquest of Ireland by the English from the mid-16th to late 17th centuries, efforts to convert the native Irish to Anglicanism through preaching in Irish faced challenges. A shortage of Anglican preachers and settlers, along with the entrenched presence of Catholicism, hindered these efforts. These campaigns highlighted nationalism among the natives, leading to a rejection of Anglican ideals and the adoption of English culture. This resistance culminated in the formal surrender of the Gaelic militias to the Crown under the Treaty of Limerick in 1691. Unlike Scotland and Wales, where many preachers promoted Protestantism in the native tongues, the Reformation in Ireland did not support Irish literature.

By the mid-18th century, English had emerged as the language of the middle class, who adopted it for social advancement. They continued to practice Catholicism, a faith far more prevalent among the Irish than Anglicanism. This shift reflected a desire for religious tolerance while pursuing greater social mobility. As opportunities for economic progress became increasingly associated with English literacy, parents began to support the prohibition of Irish in schools.

This trend was particularly evident in the eastern regions of Ireland, where English proficiency extended beyond the middle class to include the lower classes. The English writer Richard Twiss, who visited Dublin in 1775, noted that "as at present almost all the peasants speak the English language, they converse with as much propriety as any persons of their class in England." Ultimately, the combination of promoting English and preserving Catholic identity contributed to the erosion of the Irish language and its literary culture.Ó Gráda 2013. Increasing interest in emigrating to the United States and Canada was also a driver, as fluency in English allowed the new immigrants to get jobs in areas other than farming. An estimated one quarter to one third of US immigrants during the Great Famine were Irish speakers.

Irish was not marginal to Ireland's modernisation in the 19th century, as is often assumed. In the first half of the century there were still around three million people for whom Irish was the primary language, and their numbers alone made them a cultural and social force. Irish speakers often insisted on using the language in law courts (even when they knew English), and Irish was also common in commercial transactions. The language was heavily implicated in the "devotional revolution" which marked the standardisation of Catholic religious practice and was also widely used in a political context. Down to the time of the Great Famine and even afterwards, the language was in use by all classes, Irish being an urban as well as a rural language.See the discussion in

This linguistic dynamism was reflected in the efforts of certain public intellectuals to counter the decline of the language. At the end of the 19th century, they launched the Gaelic revival in an attempt to encourage the learning and use of Irish, although few adult learners mastered the language.McMahon 2008, pp. 130–131. The vehicle of the revival was the Gaelic League (), and particular emphasis was placed on the folk tradition, which in Irish is particularly rich. Efforts were also made to develop journalism and a modern literature.

Although it has been noted that the Catholic Church played a role in the decline of the Irish language before the Gaelic Revival, the Protestant Church of Ireland also made only minor efforts to encourage use of Irish in a religious context. An Irish translation of the Old Testament by Leinsterman , commissioned by Bishop Bedell, was published after 1685 along with a translation of the New Testament. Otherwise, Anglicisation was seen as synonymous with 'civilising' the native Irish. Currently, modern day Irish speakers in the church are pushing for language revival.

It has been estimated that there were around 800,000 monoglot Irish speakers in 1800, which dropped to 320,000 by the end of the famine, and under 17,000 by 1911.

The Gaelic Revival

The Gaelic revival () was the late-nineteenth-century national revival of interest in the Irish language and Irish Gaelic culture (including folklore, mythology, sports, music, arts, etc.).