Experts encourage parents to use simple sign language with  their babies as a way to communicate until they learn to SAY real  words.  I think its a great idea.  I even have Baby Sign Language for  Dummies, or whatever its called.  But, I don't use it.  I'm sure its  been successful for many parents and I tried to start with Cora, but just didn't  get into it.  I wasn't committed, I confess.  I learned the sign for  "More" to use with her as she ate, but having to put the spoon down every time I  needed to say "more" became rather frustrating for me AND for Cora.  That  girl eats FAST!  My mom tried to use that sign with Cora once after we'd  long given up on using it.  We quickly developed a running joke that the  sign for "more" actually meant "Granny" in our house.  
 Cora's been a happy baby without sign language and has  been able to communicate her needs by routine.  I would say that I never  set a routine for her, but learned to go by her cues.  Her cries were very  distinct from early on.  If she was hungry, we'd get a kind of "laaa laaa"  sound.  If she was in pain, her cry was piercing.  And if she were wet  or dirty, we could tell by the smell. (Ha!)  Her 'schedule' for her  meals and naps became predictable.  She'd wake up and want to eat first,  play for two hours, have a snack bottle, take a nap, eat lunch, take a nap, have  a snack, play a few hours, eat supper, play a few hours, have a bedtime bottle  and go to sleep, all about the same time every day.  
 Now, Cora is able to give us more definite signs of her  needs, and my favorite is her "I'm sleepy" sign.  Around 9 / 9:15 she  starts to rub her eyes and cry for a cup.  I give her milk and hold her as  she drinks it.  Then, she looks around for her paci.  I give it to her  and she pops it in her mouth.  She tries to lay down and snuggle in my  arms, but can't seem to get comfortable, so I sit her on the floor.  If she  goes after a toy, then she's not quite ready for bed--this is obviously not the  part I would call my favorite.  What I LOVE is when she finishes the cup, I  sit her on the floor, and she lays down on her belly with her bottom up in the  air and her legs pulled up underneath her.  This says "I'm sleepy,  Mommy.  Please take me to bed."  I pick her up, we go to her room, and  turn off all the lights.  I turn her lullabies on and push the ocean sounds  button on her alarm clock.  We snuggle just a few moments and I lay her in  her crib.  She falls asleep almost instantly as I pray over  her.   I turn on her humidifier before leaving the room.  The  whole routine takes about 5 minutes.  By the time I walk out and close her  door, she's sound asleep.  Sometimes I linger just to watch her  sleep. She is so precious.  
 So, its not that actual sign language didn't work for  us.  We just weren't committed to seeing it through.  Cora is a happy  and sweet little girl who understands our commands and is learning to obey  pretty well.  Her giggles, waves, cries, and laying down in the middle of  the floor communicate to us what she needs.  And we are more than happy to  give her all the GOOD things she desires!  

