Slovak uses the Latin script with small modifications that include the four diacritics (ˇ, ´, ¨, ˆ) placed above certain letters.
The primary principle of Slovak spelling is the phonemic principle. The secondary principle is the morphological principle: forms derived from the same stem are written in the same way even if they are pronounced differently. An example of this principle is the assimilation rule (see below). The tertiary principle is the etymological principle, which can be seen in the use of i after certain consonants and of y after other consonants, although both i and y are pronounced the same way.
The name Slovak is derived from *Slověninъ, plural *Slověně, the old name of the Slavs. In the Slovak language; only the masculine noun Slověninъ, Slověn changed to Slovän, Slovan and finally (under Czech and Polish influence) to Slovák around 1400. The older form Sloven is preserved in all similar words in the Slovak language - the adjective "Slovak" is still slovenský, the feminine noun "Slovak" is still Slovenka and the country is Slovensko.
The first written mention about usage of the new form Slovak in the territory of present-day Slovakia is from Bardejov (1444) - "Nicoulaus Cossibor hauptman, Nicolaus Czech et Slowak, stipendiarii supremi". The mentions in Czech sources are older - 1375 and 1385. The change is not related to ethnogenesis of Slovaks, but exclusively to linguistic changes in the West Slavic languages. The word Slovak was also used later as a common name for all Slavs in Czech, Polish and also Slovak language in parallel with other forms.