Is an interesting phenomena. As with any child, twins learn to speak by listening to those around them, and imitating the sounds as best they can, substituting sounds they can handle for ones they can't yet articulate. Since they are so closely bonded together as twin siblings, however, they more quickly pick up sounds and words from one another than from any of the adults in their lives. In other words, Curly makes a sound like "awwsigh" when trying to say "outside" and Red mangles and shortens it even farther :"sigh". So, their language can drifter even farther from the traditional English most adults may be familiar with! They may understand one another perfectly but good luck to the rest of us.
Here are some words that the girls say relatively coherently. There are probably more that I have yet to decipher:
mama, daddy, sissy, dessy, doggy, baby, uh-oh, bye-bye, no, yeah, hi, hey, pray, gone-gone, go, car, cookie, cracker, coffee, banana, bread, ok, bear, frog, bunny, puppy, kitty, bird, turtle, duck, quack, cow, moo, go away, ball, yo-yo, bug, yummy. We have really been working on "I love you", and sometimes it sounds almost recognizable. A few other words have come and gone and I'm probably forgetting some, but you get the idea. They are 20 months old as of yesterday...it's hard to believe!