Problems with Whorfian studies:
• most have not adequately utilized both the relevant linguistic and psychological research;
• most have focused on optional rather than obligatory linguistic features;
• most have not stated hypotheses in a clear, testable way, and
• most have not ruled out relevant competing Slobin-like hypotheses
Dan Slobin (1996): when speakers are using their cognitive abilities in the service of a linguistic ability (speaking, writing, translating, etc.), the language they are planning to use to express their thought will have a temporary online effect on how they express their thought. As long as language users are thinking in order to frame their speech or writing or translation in some language, the mandatory features of that language will influence the way they think.