Worked great for us - we only used about 10 signs, but things like our son suddenly at the table refusing all food and waving randomly at the table - so we asked (rhetorically) 'fine! What do you want?' And he signed "water". After a swig he happily carried on eating. Also our daughter running up to us (11 months) and signing she wanted her diaper changed. Sure enough...

We have other friends with similar aged kids who's kids get incredibly frustrated when they cannot communicate something like that and just scream until the parents five then what they want.

Our kids did use it both differently, and different amounts, but it was a minor helpful extra for us.