Kyrgyz is a Turkic language that has the usual characteristics of that language group, most notably vowel harmony, which is strictly adhered to (with the exception of Slavic and Persian loan words). As part of the Kyrgyz-Altay group of Turkic languages it is most closely related to the Altay language and fairly similar to Kazakh.
Modern Kyrgyz did not have a standard written form until 1923, when an alphabet using Arabic characters, like Ottoman Turkish, was introduced (this is still used by the Kyrgyz population of Xinjiang, China). This was changed to a Latin-based alphabet in 1928, which in turn was replaced in 1940 by the modified Cyrillic alphabet that is still in use today. Following independence, there have been some suggestions of reverting back to the Latin alphabet, as has been the case in Uzbekistan, but this has not been followed through, probably because the Cyrillic suits the language well.
Modern day Kyrgyz may be divided into two distinct groups of different dialects. Standard Kyrgyz was defined during the Soviet period as the northern variation of the language that has a large number of loan words from Mongolian languages, whereas the southern dialects contain far more words from the Uzbek, Persian and Tajik languages. Modern Kyrgyz naturally also has a large number of words of Russian derivation in its vocabulary.
When Kyrgyzstan was an autonomous republic within the Soviet Union, Russian was the official language of state, but immediately following independence in 1991, Kyrgyz was promoted as the official language, and in 1992 a law was passed that called for all public business to be converted fully to Kyrgyz by 1997. Kyrgyzstan's Russian-only speakers were strongly against this move and public opinion was so critical that it even caused an ethnic Russian member of President Akaev's staff to threaten resignation as a protest against what he saw as the 'Kyrgyzification' of the new republic's non-Kyrgyz population.
In response to this and other, more widespread, protests, a resolution was passed in 1996 to make Russian an official language of state alongside Kyrgyz. This move, which reversed the earlier commitment and bucked the trend of other central Asian states that had demoted Russian as the language of state, was meant to encourage ethnic Russians to remain in the new republic and not take their skills elsewhere, although by this stage many had left anyway.
It was a pragmatic reversal in many respects, considering that other minorities such as Uzbeks spoke their own tongue, not Kyrgyz, in addition to Russian, and that for many northern, urban Kyrgyz, Russian was both their mother tongue and the preferred language of business and politics. Nevertheless, since independence use of the Kyrgyz language has been encouraged to the extent that it is now the main language of parliament. The current constitution states that it is necessary for the president to be a fluent speaker of the language.
Apart from Russian, of which almost all Kyrgyz citizens have some knowledge and in which many are fluent, the other widely spoken language in the country, though commonest in the south, is Uzbek, spoken by Kyrgyzstan's sizeable Uzbek minority. Like Kyrgyz, Uzbek is a Turkic language but, unlike Kyrgyz, it belongs to the Qarluq family of Turkic languages and is closely related to Uyghur. On the whole, Islam has had a greater effect on the Uzbek language than it has on Kyrgyz, and as a result Uzbek has a greater proportion of Persian and Arabic loan words. While in neighbouring Uzbekistan the language is now written using an adapted Latin script, in Kyrgyzstan a Cyrillic alphabet is still in use.