A disadvantage in bilingual sentence production modulated by syntactic frequency and similarity across languages

• Bilinguals are slower than monolinguals in producing full sentences.
• Syntactic retrieval imposes a bilingual disadvantage above and beyond lexical retrieval.
• Sentence production speed is modulated by experience with syntactic structures.
• Cross-language syntactic interactivity impacts conversations held in one language.

Bilingual speakers access individual words less fluently, quickly, and accurately than monolinguals, particularly when accessing low-frequency words. Here we examined whether the bilingual speech production disadvantage would (a) extend to full sentences above and beyond single word retrieval and whether it would be modulated by (b) structural frequency and (c) syntactic properties of the bilingual speakers’ other language. English monolinguals, Spanish–English bilinguals and Mandarin–English bilinguals were tested in a sentence production task conducted exclusively in English. Response times were modulated by bilingualism, structural frequency, and structural similarity across the bilingual speakers’ two languages. These results refine our knowledge regarding the scope of the bilingual disadvantage, demonstrate that frequency effects apply to syntactic structures, and also suggest that syntax is partially shared across bilinguals’ two languages.