Every person charged with a crime has a right to the assistance of an interpreter where they cannot understand the English or French language. Section 14 of the Charter states:
14. A party or witness in any proceedings who does not understand or speak the language in which the proceedings are conducted or who is deaf has the right to the assistance of an interpreter.
Interpretation must be continuous, precise, impartial and contemporaneous. 
This right requires that the interpreter be a competent one. This does not mean that s. 14 of the Charter extends guarantee to an accredited or certified interpreter. The interpreter must simply be a competent and qualified court interpreter. Unaccredited interpreters will often be held to be inadequate.
To determine whether an interpreter is sufficiently competent the court must look at "the nature of the accreditation and the validity of the test upon which it is based, the test results attained, the mode of interpretation required, the expected length of the proceedings, and the technical nature of the subject matters in the proceeding."
Before an interpreter can testify, he must be sworn.
- Canadian Charter of Rights and Freedoms section 14
- R v Wong, 2011 ONCJ 264 (CanLII) at para 20
R v Rybak, 2008 ONCA 354 (CanLII),  O.J. No. 1715, at para 84
R v Sidhu, 2005 ONCJ 8 (CanLII),  O.J. No. 4881
- See R v Sidhu, 2005 CanLII 42491 (ON SC), (2005) 203 CCC (3d) 17 at para 298
- R v Tran, 1994 CanLII 56 (SCC), (1994) 92, CCC (3d) 218 (S.C.C.)
R v N.S.  OJ No 3255(*no link)
R v Thillayampalam, 2011 ONCJ 800 (CanLII), at para 8
- R v Dutt, 2011 ONSC 3329 (CanLII) at para 12
- R v Tran, 1994 CanLII 56 (SCC),  2 SCR 951 at p. 988 ("an interpreter must at least be sworn by taking the interpreter’s oath before beginning to interpret the proceedings")