Animal Talk
Animal Talk is a concept and practice of communication between humans and animals for various reasons from sense of connection and playful "trick show-off" to communication with animals who cannot hear, such as deaf dogs, to research (eg. Koko the Gorilla and Washdoe the Chimpanzee). A classic example is Roger Fouts and Washoe (chimpanzee) who communicated in adapted sign language.
Human interest in communicating with animals (and perhaps true for vice versa) has been around for a long time. Dolphins, parrots, and elephants are examples. Not all animals rely on hands and eyes to communicate. Parrots use voice. Apes use hands. Some draw or paint. Communication is not limited to the hearing domain. Visual communication is also largely used (signing, drawing, painting, body language, etc.) within the whole communication.
Communication Mediums
Since animals and humans use different their body parts to communicate. Hearing people use ears, vocal chord and gesturing hands. Deaf people use hands, eyes, and faces. Animals use various parts of what they can communicate with by either signing, listening, vocalizing and/or responding to body language, visible gestures or actions.
Learning Signs
Like humans, it is best to begin teaching signs to animals at the earliest possible -- at birth -- throughout the training. It is never too late to start at any age, nevertheless.
There are many ways of teaching and communicating with animals, depending on what kind of animals. Many owners, animal scientists and researchers use Sign Languages already developed by Deaf people to communicate with animals.
Sometimes, the masters use few of their own "jargons", signs or singals. For example, dog owners can have their own preference, using "clap" movement for "good" while others may prefer "thumb-up" signal for "good".
When communicating in Sign with animals who can hear, naturally it is good to use voice accompanied.
Training Resources
Handspeak offers the dictionary of signs that you can learn and use some signs (eg. sit down, come here, etc.) For training, obedience class, etc., please consult the web resources, books, etc. or see the "Directory and Shop" link at www.handspeak.com.
If you have any experiences with using signs with your animals to share with readers, you are welcome to write an email to HandSpeak.