Even deaf kids dont sign the same as momma and daddy... just like little ones dont say words like adults... they do the best they can. I love that phase....
Did she list more/want/please along with important names of people and things? Unless she disagrees for some reason, you might want to add one or all of those. They are the "power" words so that if she does not have a word for an item she can still make the request in some way.... this highly reduces frustration. (along with a way to say NO which is often clear but she may not have a word yet so can work on that) So, when you feed her or do a game with little pieces like shapes or balls that drop thru a maze... you can do one at a time and then just hold off.... not to tease but to give time to ask for "more' or to say "please" then use that as a request and say... More puzzle or more milk etc...-- Another fun activity is like bouncing on your knee-a horsie ride- and stop, wait for the "more" sign... or on a swing and catch the swing...dont let go till she says please.... etc. You can model it if she forgets-- then, build by ONE word above where she is in order to allow for more chances of imitating... so if she is not verbalizing at all .... then just say the sign... if she can say a word (mom with mom sign) then you can add one more word to it (mommy eat). Dont have to wait for her to imitate...just give the model. After time they tend to start to imitate..... These are just general language therapy guidelines and since she catches on so fast sounds like she will do so well. You must have a natural way with teaching her and it is a good sign that this is not a more pervasive developmental disorder if she is picking up the language so easily. I hope that lasts for her.
This is not to say dont ever talk in more than one word or two words. When giving directions or asking questions, talk like you would talk to any 1 1/2 year old. That is for comprehension. But when working on expressive language (again, unless your therapist gave you other guidelines since she is actually seeing her and her level) do the just say one word above what she is saying in terms of length of statement.
Sounds like therapist is a good listener and flexible... I am so glad for you. YIPEE for sweat pea! There are lots of online ASL websites now so you can actually see how to make a sign..... like dictionaries but with movies so much better than a book if you are ever wondering about a sign. Have fun! When you are done you are going to be a speech/lang path... you have gone thru so much with all of your kids!