Mark Shekleton’s review published on Letterboxd :
Brit Marling is 2 for 2 in starring in and co-writing quality films telling human stories with sci-fi underpinnings (this, along with Another Earth). Sound of My Voice maintains a quick pace as it feeds you clues supporting both sides of the core mystery of the story. Just when you think you've got it figured out, it throws you back off course, keeping you guessing up to and even past the tense ending scene. Marling's Maggie shows a range of traits, appearing at times as a nurturing and supportive teacher, or a playful free-spirit, or a menacing and commanding authoritarion. Essentially what I'm saying is... MORE BRIT MARLING IN ALL THINGS PLEASE!