What is the difference between the supine and the past participle? In English, it is the infinitive preceded by "to" as in "to go", "to say" and "to want". In Swedish, however, it functions as a past participle.
In the sentences "I have closed the window" and "The window is closed" the word "closed" serves different functions. In the first sentence the verb "closed" is preceded by the auxiliary verb "have" and together they form the present perfect tense. In the second sentence, "closed" is preceded by the verb "is" and functions as an adjective. The term for these in English is the past participle.
The Swedish language has two forms of the English past participle. They are the supine and the past participle. The supine is always used after the auxiliary verb "have" as in "Jag har stängt fönstret" (I have closed the window).
The past participle functions like an adjective and agrees with the noun it modifies in gender and number. Compare the following examples:
(common gender) Restaurangen är stängd idag. (The restaurant is closed today).
(neuter gender) Biblioteket är stängt. (The library is closed).
(plural) Broarna är stängda. (The bridges are closed).
The term supine has a different meaning from language to language. This is the case in English and Swedish. The Swedish supine corresponds to the English past participle and occurs after the auxiliary "have". However, the Swedish past participle functions as an adjective and agrees with its subject in gender and number.