The evidence gathered in the present study supports the use of the simultaneous development of test items for different languages. The simultaneous approach used in the present study involved writing an item in one language (e.g., French) and, before moving to the development of a second item, translating the item into the second language (e.g., English) and checking to see that both language versions of the item mean the same. The evidence collected through the item development stage suggested that the simultaneous test development method allowed the influence and integration of information from item writers representing different language and cultural groups to affect test development directly. Certified English/French translators and interpreters and the French Immersion students confirmed that the test items in French and English had comparable meanings. The pairs of test forms had equal standard errors of measurement. The source of differential item functioning was not attributable to the adaptation process used to produce the two language forms, but to the lack of French language proficiency as well as other unknown sources. Lastly, the simultaneous approach used in the present study was somewhat more efficient than the forward translation procedure currently in use. (Contains 5 tables and 5 footnotes.)