please explain the former.
The term "Old Czech" is applied to the period predating the 16th century, with the earliest records of the high medieval period. The Bohemian (Czech) language is first recorded in writing in glosses and short notes during the 12th to 13th centuries. Literary works written in Czech appear in the late 13th and early 14th century and administrative documents first appear towards the late 14th century. The first complete Bible translation also dates to this period. Old Czech texts, including poetry and cookbooks, were produced outside the university as well
Czech language
The term "Old Czech" is applied to the period predating the 16th century, with the earliest records of the high medieval period also classified as "early Old Czech", but the term "Medieval Czech" is also used.

Around the 7th century, the Slavic expansion reached Central Europe, settling on the eastern fringes of the Frankish Empire. The West Slavic polity of Great Moravia formed by the 9th century. The Christianization of Bohemia took place during the 9th and 10th centuries. The diversification of the Czech-Slovak group within West Slavic began around that time, marked among other things by its use of the voiced velar fricative consonant (/ɣ/) and consistent stress on the first syllable.

The Bohemian (Czech) language is first recorded in writing in glosses and short notes during the 12th to 13th centuries. Literary works written in Czech appear in the late 13th and early 14th century and administrative documents first appear towards the late 14th century. The first complete Bible tra
what is the main language in czech republic Czech how is it classified? Czech is distinguished from other West Slavic languages by a more-restricted distinction between "hard" and "soft" consonants does it have older and more recent versions? Yes,  "Old Czech" and "Modern Czech"
wiki:1611693
Czech language [SEP] Medieval/Old Czech
The term "Old Czech" is applied to the period predating the 16th century, with the earliest records of the high medieval period also classified as "early Old Czech", but the term "Medieval Czech" is also used. Around the 7th century, the Slavic expansion reached Central Europe, settling on the eastern fringes of the Frankish Empire. The West Slavic polity of Great Moravia formed by the 9th century. The Christianization of Bohemia took place during the 9th and 10th centuries. The diversification of the Czech-Slovak group within West Slavic began around that time, marked among other things by its use of the voiced velar fricative consonant (/ɣ/) and consistent stress on the first syllable.