I suggest that you use realia, and give them activities in which they handle the realia and learn to associate the word and the thing.
There are some forum threads about teaching kindergarten and other young students. Check those out.
And look at this site, which is jam-packed full of free resources:
Free Printables for Teachers - Free flashcards, printable games, free worksheets, printables, phonics, clipart, projects, ebooks and other resources
Probably they can't read in their native language, so getting them to read in English will be difficult.
Did you teach them the alphabet? Phonics? They need both.