Is the bilingual language production system a dynamic system that can operate in different language activation states? Three experiments investigated to what extent cross-language phonological co-activation effects in language production are sensitive to the composition of the stimulus list. L1 Dutch–L2 English bilinguals decided whether or not a particular phoneme was part of the L2 English name of the picture. The phoneme was either part of the English name of the picture (/b/ or /t/ in bottle), the Dutch name of the picture (/f/ in fles [bottle], the cross-language condition), or was not part of either the English or Dutch names of the picture (/p/, the unrelated condition). In Experiment 1, we added a set of filler pictures with noncognate names in Dutch and English. In contrast, the filler pictures in Experiment 2 all had cognate names in Dutch and English. In Experiment 3 the fillers consisted of a mixture of pictures with cognate (25%) and noncognate (75%) names. Cross-language phonological co-activation appeared sensitive to the composition of the stimulus list: Phonological co-activation effects were observed in Experiments 2 and 3, but not in Experiment 1. The results indicate that the bilingual language production system dynamic and can operate in different modes, depending upon the composition of the stimulus list. We discuss implications for experimental paradigms used in the field of bilingual language production, and for current bilingual language production models.