By about 1500, the chief characteristics of Danish had evolved, and it began to be used as a national language. The printing and publishing activities that occurred during the Reformation led to a considerable transformation of the medieval orthography and contributed markedly to the development of a literary vocabulary. A geographical expansion of Danish took place when it became the official written language of Norway, which was then united with Denmark. Under the influence of humanism, Latin was used extensively in literary writing from about 1550 to about 1700. During the last half of the 17th century, German was spoken at the royal court, and many German words entered the Danish language; most of them were later discarded. Danish had virtually completed its grammatical development by the beginning of the 18th century, and it became a significant cultural and literary language, especially through the work of the poet, playwright, and historian Ludvig Holberg.

In the 19th and 20th centuries, fewer dialects were spoken, the interaction between spoken and written language increased, and the vocabulary expanded through the assimilation of German, French, and English words, including many technical terms. An authorized standard orthography, with subsequent revisions, has been in effect since 1871. Through a spelling reform adopted in 1948 the capitalization of nouns was abolished, and the letter aa was replaced by å, which brought Danish closer to Norwegian and Swedish.

The most notable features of today's Danish are: in phonetics - usage of the glottal stop consonant sound, and of softened consonants b, d, g; in morphology - the definite article as in Western Germanic languages. These are unique in Danish and distinguish it from Swedish, Icelandic and other Scandinavian tongues.