Hi Blue,
For my boy, i never use flash card and do not really know how to use it.
I normally use a pictue (of a book)or toys or our body parts as an aid to teach him, after few rounds of teaching, he'll point out the picture/object according to what i want. Now he 'd already known " car, pacifier,bowling pin, ball,sun, grapes,teddy bear,clock,zebra, eyes, hand "
Now he can understand our instructions to "wave bye bye, high 5, clap hands, hurray, beat beat, drink, come,stop, kiss "
so i believe some bbs able to response more not only from a card, oso can try real object