Sign approximations are something you come across often in the baby sign language world. It stems from the fact that tiny baby fingers have very little fine motor coordination. ASL wasn’t designed for their dexterity and lack of precision. For this reason, baby who sign often do their very best, but it only appears as some close version of the true sign.
In fact, most signs your baby does will appear as sign approximations. A baby usually leaves out the various handshapes, the complex movements and sometimes even the proper location where the signs should be preformed. Some babies might even do several signs that look almost identical. These signs can only be distinguished from other similar signs through context. While you might think baby is just trying to pull a fast one on you, he’s actually trying to do the sign and likely thinks he’s doing it properly. What is important, is that you reward these early attempts. Just like talking never comes out perfect, neither do signs and you wouldn’t hold back on your congrats just because it wasn’t perfect out of the gate.
I will make this point loud and clear, your baby is always trying to do their best. When they come up short, it’s not because they are somehow slacking off, or giving up, or doing it on purpose to drive you bananas. A baby is always trying to please those he looks up to in the best way possible.