Willingness to communicate (WTC) is considered to be an important factor contributing to successful foreign language learning. Many studies aim at finding effective tools for enhancing WTC. With the support of AI and Automatic Speech Recognition technology, intelligent personal assistants (IPAs) seem to have potentials in improving foreign language learners' WTC. However, few empirical studies focus on the possible impact of IPAs on learners' WTC. This study was conducted to investigate the potentials of an IPA, Google Assistant, for developing adolescent EFL learners' WTC and their perceptions of IPAs for EFL learning. This study recruited 112 eighth-grade EFL learners who engaged in Google-Assistant-language-learning activities for two weeks. Two WTC questionnaires were administered at the beginning and end of the intervention. The results demonstrated that Google Assistant significantly promoted EFL learners' WTC, enhanced communicative confidence, and reduced speaking anxiety. Analyses of interviews revealed that participants enjoyed playing games with Google Assistant and talking to chatbots, which helped them feel less anxious and motivated to use English for real and meaningful communication. The findings indicated that IPA-based interaction provided a less threatening environment, in which learners displayed higher levels of engagement, motivation, confidence, and, in turn, their WTC in the target language.