The Baltic languages are of particular interest to linguists because they retain many archaic features believed to have been present in the early stages of the Proto-Indo-European language.
There is some evidence to suggest the existence of a Balto-Slavic language group after the break-up of Proto-Indo-European, with the Slavic and Baltic languages splitting around the 10th century BC. However, some linguists: Meillet, Klimas, Zinkevičius oppose this view, providing arguments against Balto-Slavic group, and explaining similarities by one or several periods of close contacts. As there exist a number of Baltic words that are similar to Sanskrit or Latin, which lacks counterparts in Slavic languages. Latvian with Albanian, slavic and Indo-Iranian languages are grouped as satem languages. While the possession of many archaic features is undeniable, the exact manner by which the Baltic languages have developed from the Proto-Indo-European language is not clear.
According to some glottochronological speculations, the Eastern Baltic languages split from Western Baltic (or, perhaps, from the hypothetical proto-Baltic language) between 400 and 600. The differentiation between Lithuanian and Latvian started after 800, with a long period of being one language but different dialects. At a minimum, transitional dialects existed until the 14th century or 15th century, and perhaps as late as the 17th century.
Latvian emerged as a distinct language in the 16th century, having evolved from Latgalian and assimilating Curonian, Semigallian and Selonian on the way. All of these belong to the Baltic language group.
The oldest known examples of written Latvian are from a 1530 translation of a hymn made by Nikolaus Ramm, a German pastor in Riga.
Until the 19th century, the Latvian language was heavily influenced by German language, because upper class of local society was formed by Baltic Germans. In middle of 19th century first Latvian National Awakening was started, led by “Young Latvians” who popularized use of Latvian language, participants of this movement laid foundations for standard Latvian and also popularized latvianization of loan words. However in 1880s when tsar Alexander III came into power, Russification started, during this period some Latvian scholars even suggested adopting the Cyrillic alphabet for use in Latvian. After the tsar's death, at the turn of the 19th and 20th centuries, nationalist movements reemerged.
In 1908, Latvian linguists Kārlis Mīlenbahs and Jānis Endzelīns elaborated the modern Latvian alphabet, which slowly replaced old orthography used before. Another interesting feature of the language, in common with its sister language Lithuanian, that was developed at the time is that proper names from other countries and languages, no matter how obscure, are altered phonetically to fit the phonological system of Latvian. Even if the original language also uses the Latin alphabet, this process takes place. Moreover the names are modified to ensure they have noun declension endings, declining like all other nouns. For example a place such as Lecropt (a Scottish parish) is likely to become Lekropta; the Scottish village of Tillicoultry becomes Tilikutrija. This is a good example of linguistic purism in this ancient language.
During the years of Soviet occupation (1940–41 and 1945–91) the policy of Russification greatly affected the Latvian language. Through these periods many Latvians and Latvia’s other ethnicities faced deportations and persecutions. A massive immigration from the Soviet republics of Russia, Ukraine, Belarus and others followed, largely the result of Stalin's plan to integrate Latvia and the other Baltic republics into the Soviet Union by means of Russian colonisation. As a result, the proportion of the ethnic Latvian population within the total population was reduced from 80% in 1935 to 52% in 1989. In the Soviet Latvia, most of the immigrants who settled in the country didn't learn Latvian. Today, Latvian is the mother tongue of more than 60% of the country's population.
After the re-establishment of independence in 1991, a new policy of language education was introduced. The primary goal declared was the integration of all inhabitants into the environment of the official state language, while protecting the languages of Latvia's ethnic minorities.
Government-funded bilingual education is available in primary schools for ethnic minorities. These include Russian, Jewish, Polish, Lithuanian, Ukrainian, Belarusian, Estonian, and Roma schools. Latvian is taught as a second language in the initial stages to encourage proficiency in the language, aiming to avoid alienation from the Latvian-speaking linguistic majority and to facilitate academic and professional achievement. Since the mid-1990s, the government may pay a student's tuition in public universities only provided that the instruction is in Latvian. Since 2004, the state mandates Latvian as the language of instruction in public secondary schools (Form 10–12) for at least 60% of class work. (Previously, a broad system of education in Russian existed.)
The Law on State Language was adopted on December 9, 1999. Several regulatory acts associated with this law have been adopted. The observance of the law is monitored by the State Language Centre run by the Ministry of Justice.
To counter the influence of Russian and English, government organizations (namely the Terminology Commission of the Latvian Academy of Science and the State Language Center) try to popularize the use of Latvian terms and linguistic purism. Purism is often observed in the coining of new terms, which are usually disputed by the public — although purists have invented some euphonic words, many neologisms are widely seen as 'alien' and unnecessary, as pre-existing words could be used instead; for example, a heated debate arose when the Terminology Commission suggested that “eira”, with its 'latvianized' ending, would be a better term for euro than the widely used “eiro”. Other new terms are literal translations or new loanwords. For example, Latvian has two words for "telephone" – "tālrunis" and "telefons", the former being a direct translation into Latvian of the latter international term. Still others are older, more euphonic loanwords rather than Latvian words. For example, "computer" can be either "dators" or "kompjūters". Both are loanwords (the native Latvian word for 'computer' is "skaitļotājs"). However, for some time now “dators” has been considered an appropriate translation.
There are several contests held annually to promote correct use of Latvian. Notably, the State Language Center holds contests for language mistakes, named "Gimalajiešu superlācis" after an infamous incorrect translation of Asiatic Black Bear. These mistakes, often quite amusing, are both grammatical and stylistic; sometimes also obvious typos and mistranslations are considered to belong here. Organizers claim that mistakes are largely collected in areas heavily populated by Russians-speakers, as well as from Lithuanian-owned chain stores. Mistranslations are not necessarily grammatical, but also stylistic and vocabulary mistakes, such as literal translations from the English language.