We examined if bilinguals of two different language combinations can rely on novel and arbitrary cues to facilitate switching between languages in a read-aloud task. Spanish-English (Experiment 1) and Hebrew-English (Experiment 2) bilinguals read aloud mixed-language paragraphs, known to induce language intrusion errors (e.g., saying el instead of the), to test if intrusion rates are affected by: language combination, color-cues, language dominance, and part of speech. For Spanish-English bilinguals, written input is not rich in visual cues to language membership, whereas for Hebrew-English bilinguals rich cues are present (i.e., the two languages have different orthographies and are read in opposite directions). Hebrew-English bilinguals made fewer intrusion errors than Spanish-English bilinguals, and color cues significantly reduced intrusions on switches to the dominant language but not to the nondominant language, to the same extent in both bilingual populations. These results reveal powerful effects of visual cues for facilitating production of language switches, and illustrate that switching mechanisms are highly adaptable and sensitive, in that they can both recruit language- and orthography-specific cues when available and also rapidly exploit novel arbitrary cues to language membership when these are afforded. Finally, such incidental, experimentally induced cues, were recruited even in the presence of other already powerful cues, when task demands were high.