By age two, the average non-signing toddler carries a vocabulary of around 50 words. These words are spoken of course since they haven’t been given the power to sign. The average signing toddler, however, will have a vocabulary of 150-300 words, some of which will be spoken and others signed. This is very significant especially moving forward. For now, let’s just point out that as far as language and vocabulary goes, there is no practical difference between a signed word and a spoken word. According to development, they are both the exact same and utilize very similar neural pathways in a baby’s brain. To make this clear, you wouldn’t say that a deaf person has a vocabulary of zero, would you? Therefore, all words, spoken or signed, count in a baby’s vocabulary. When a person can communicate a sign, they understand what it means and what performing the sign can do for them.
So why is having up to three times as many words in a two-year-old signing baby’s vocabulary over a non-signing baby so important? Well the simple answer is that it’s moving everything forward by just that much. Vocabulary growth is a cumulative event and also happens exponentially. Therefore, it starts off slowly, perhaps adding a sign each month but once a sufficient base of words exist, new words are added weekly and then at around 15-30 signs, words can be added every other day or even daily referred to as the signing explosion. True exponential grow usually happens at around 30-60 words at 14 months of age. The natural progression of course, is to then start combining words into sentences which is another milestone altogether. Sentences are a natural progression of having a large enough vocabulary to form meaning by coupling words.
Signing helps babies reach the critical level where exponential growth can happen sooner. This threshold is what makes signing so effective because once the critical level is reached, vocabulary growth expands, and for signing babies, this communication milestone is brought forward by a significant degree over non-signing babies. In fact, as signing babies enter the exponential stage, non-signing babies are just beginning to add their first few words. Why wait until a baby’s physical capacity has caught up to their processing abilities? Why not give them the tool to start communicating right away.
Above: The story of the broken airplane! Then I show you a technique for teaching the sign for BREAK by using a stick we found outside.