Part one ORGANISATION OF COURTS
Chapter 5
RIGHT OF PUBLIC ATTENDANCE AND MAINTENANCE OF ORDER AT COURT HEARINGS
Section 6
If a party, a witness, or any other person who shall be heard by the court is incapable of understanding and speaking Swedish, an interpreter may be engaged to assist the court.
If an public interpreter for the language in question serves at the court, he shall be assigned. Otherwise, the court shall assign a suitable person to assist as interpreter in the case.
If the person to be heard has a serious hearing or speaking impediment, an interpreter may also be engaged to assist the court.
A person whose interest in the matter at issue, or whose relationship to any of the parties, could be considered to cast doubt on that person's reliability, may not be engaged as an interpreter.
The government shall issue regulations concerning both the employment of public interpreters and the assignment of interpreters when the person to be heard has a serious hearing or speaking impediment.
Rights during investigation - access to interpreter and translation if questioned in other language
Rights during trial - interpretation and translation
EDIT.