In what places do you think Alma and his people prayed in their hearts? It's good to pray outloud when possible, it helps us to concentrate. But the Savior has asked us to "Pray Always" (3 Ne 18:15, among others - read this verse if you have time). Are there places where it might be better for you to pray in your heart? What about in school, especially when the teacher is teaching? What about during the sacrament ordinance? Draw pictures of places where it might be better to pray in your heart than to pray outloud.