In this paper, an approach for polyglot speech synthesis based on cross-lingual frame selection is proposed. This method requires only mono-lingual speech data of different speakers in different languages for building a polyglot synthesis system, thus reducing the burden of data collection. Essentially, a set of artificial utterances in the second language for a target speaker is constructed based on the proposed cross-lingual frame-selection process, and this data set is used to adapt a synthesis model in the second language to the speaker. In the cross-lingual frame-selection process, we propose to use auditory and articulatory features to improve the quality of the synthesized polyglot speech. For evaluation, a Mandarin-English polyglot system is implemented where the target speaker only speaks Mandarin. The results show that decent performance regarding voice identity and speech quality can be achieved with the proposed method.