On first inspection it might seem to make sense to have as many words as possible inside of the baby sign language dictionary, but this it’s so. For starters, most babies will never learn to sign fluently in ASL. For the vast majority, signing will be a bridge between babbling and talking. In my experience and research, a baby will learn about 20-30 words. Some might only pick up 10-15. Others, the start signers (read star parents) will learn up to 150 words. Once baby has learned this many, they understand how language works and have the basic coordination to start adding words. At this point in time, you’ll be chasing your little guy around trying to steady them to teach them signs. In other words signing is going to take a back seat to the dynamics of life. Talking can happen with great ease, it requires little focus and comes naturally within the context of a busy life.
So if you push really hard, you might get over 200 words and if you’re hell-bent, might even sign all 350 plus words. However, once you reach this level, there are plenty of resources better adapted to teaching sign language that can’t be hand via this program. There are many programs online that teach the full language including syntax and grammar that babies don’t require. The baby sign language program is just a way to introduce key words to your baby’s life. That’s why it includes words for things that most babies find interesting. If the dictionary had all the words, then the ones that are easiest for a baby to do would get muddled with the rest and so you’d be left at a greater disadvantage.
In other words, more isn’t always better. The baby sign language dictionary is tailor-made to the needs of babies and includes those words which are most likely to be adopted.