"She speaks Danish."
Translation:Hun snakker dansk.
In Danish, only names, place names (street names, countries, towns etc), and a few other words (like the name of some institutions) are capitalized.
So, unlike in English, languages, nationalities (and other place-adjectives), months, days, compass directions etc. are not capitalized
Dansk is singular and danske is plural. The singular dansk is also used to refer to the language.
en dansk mand / a Danish man
et danske æble / a Danish apple
danske mænd / Danish men
danske æbler / Danish apples
Jeg taler dansk. / I speak Danish.
It works the same way with the rest of the languages, like engelsk or kinesisk.