Listen and speak (LAS)is a useful augmentative and alternative communication (AAC) APP. It can help people who can not express themselves verbally to communicate their needs and thoughts. LAS has self-built vocabulary set and word prediction function that can help those who have difficulty writing. Its main functions are as follows: 1. It has pre-designed ten vocabulary set, so AAC users can use it to quickly communicate with others. Meanwhile, the speech language pathologist or the special educator can copy and modify the pre-designed vocabulary set to a new set, based on the needs of the AAC user. 2. It has the menu of communication history. Therefore, the user can select from the menu and directly express the message they have constructed to the communication partner, without having to reconstruct the sentence. 3. It has the menu of my favorite sentence. AAC users can edit their favorite sentences based on the communication situation they are in. 4. It has flipped function. In a noisy environment, the communication partners can understand the message from AAC users from the opposite side of the device.