Germanic languages: Old Swedish
Old Swedish belongs to the Scandinavian branch of the Germanic languages, a subfamily of Indo-European languages. It is an eastern development of the language known as Dænsk tunga (Danish tongue), which was spoken in all of Scandinavia even before the early Middle Ages.
The Swedish branch of this common tongue developed into a separate language from 900 to 1500 AD; the oldest period (900-1225) is known as Runic Swedish. The Latin alphabet was introduced in the 13th century; periods of further differentiation followed, and some approximation to Danish occurred. This latter period (1225-1500) is known as Old Swedish. The written language, based on two of the most widely spoken dialects, was made uniform throughout Sweden in the 14th century.
There was some nowadays obsolete characters in Old Swedish. If you cannot input them, try the following:
Old Swedish verbs were grouped in two major groups: weak verbs and string verbs. They differ in they way of forming the past tense. Weak verbs form the past tense with a dental suffix (þ, d, t), e.g., kalla -- kallaþe. Strong verbs form the past with vowel shift in the root of the verb.
Due to different vowel shifts, strong verbs were grouped in 6 categories.