Though stages of language development are never as sharply delimited as implied here, and should not be taken too literally, the system of subdivisions used in this article is the most commonly used by Swedish linguists and is used for the sake of practicality.
The innovations spread unevenly from Denmark which created a series of minor dialectal boundaries, isoglosses, ranging from Zealand to Svealand.
Among the most important documents of the period written in Latin script is the oldest of the provincial law codes, Västgötalagen, of which fragments dated to 1250 have been found.
The main influences during this time came with the firm establishment of the Catholic Church and various monastic orders, introducing many Greek and Latin loanwords.
Besides a great number of loan words for areas like warfare, trade and administration, general grammatical suffixes and even conjunctions where imported.
Early medieval Swedish was markedly different from the modern language in that it had a more complex case structure and had not yet experienced a reduction of the gender system.
A transitional change of the Latin script in the Nordic countries was to spell the letter combination "ae" as æ – and sometimes as a' – though it varied between individuals and regions.
The Vasa the holy Bible is often considered to be a reasonable compromise between old and new; while not adhering to the colloquial spoken language of its day it was not overly conservative in its use of archaic forms.
It established the use of the vowels "å", "ä", and "ö", and the spelling "ck" in place of "kk", distinguishing it clearly from the Danish Bible, perhaps intentionally due to the ongoing rivalry between the countries.
Some important changes in sound during the Modern Swedish period were the gradual assimilation of several different consonant clusters into /ɧ/ and the softening of /g/ and /k/ into /ʝ/ and /ɕ/ before front vowels.
Many authors, scholars, politicians and other public figures had a great influence on the new national language that was emerging, the most influential of these being August Strindberg (1849–1912).
The use of herr ("mr"), fru ("mrs") or fröken ("miss") was only considered acceptable in initial conversation with strangers of unknown occupation, academic title or military rank.
The fact that the listener should preferably be referred to in the third person tended to further complicate spoken communication between members of society[citation needed].
In the early 20th century, an unsuccessful attempt was made to replace the insistence on titles with Ni (the standard second person plural pronoun) – corresponding to vous in French and Sie in German.
With the liberalization and radicalization of Swedish society in the 1950s and 60s, these previously significant distinctions of class became less important and du became the standard, even in formal and official contexts.