Dateline: February, 2008, Issue 3
Are witnesses who don't speak English less credible to jurors?
Takakawa (1999) had members of a jury pool in Hawaii listen to direct examination of witnesses, including speakers of Standard English and Hawai'i Creole English. Jurors judged speakers of Standard English as most credible.
Stephan and Stephan (1986) found that non-Hispanic jurors judged Spanish speaking and Thai speaking defendants who testified through a translator as more likely to be guilty than English-speaking defendants. Judicial instructions admonishing jurors to ignore the fact the defendant's testimony was translated eliminated the bias jurors exhibited against the non-English-speaking defendants.
In sum, jurors exhibit bias against non-English speaking defendants which judicial instructions can reduce.
Source Takakawa, N. N. (1999). A study of jurors' attitudes toward testimony in Hawai'I Creole English. Masters Abstract International, 37, p. 1612.
Source Stephan, C.W. & Stephan, W. G. (1986). Hable Ingles? The effects of language translation on simulated juror decisions. Journal of Applied Social Psychology, 16, pp. 577-589.