Here are some writing samples from their ongoing outer space project.
This is D1’s original composition. She is starting to use capitals for the beginning of sentences, although I don’t see any periods. Her words are distinct entities, no longer all run together. She has memorized the spelling of "love" from much repetition in notes, but doesn’t know that "have" is similar. She knows how to spell the "oo" and "oy" sounds but makes up her own combinations for other vowel digraphs ("aw" for "ou"). On this whole page she only misses one consonant sound: the "n" in windows. (No, those aren’t "widows" on the rocket. :-P)
This portion she copied from a book about space travel. When copying, she does use periods as well as capitals and apostrophes properly. She tries to copy the form of the letters down to reproducing the typeface style of "a" and "g." Apparently she gave up before copying "gravity." Her "s" is backwards even when copying.
D2 is quite a bit harder to decipher, but he’s only four and four months. He sounded out all the sounds in "front" and "start" by himself (both he and D1 tend to mistake the voiced for the unvoiced consonant when sounding out: "sdort" for "start," "sbas" for "space." I think this is a natural consequence of the force given when concentrating on the individual sound, but I’m not sure how to help them out of it. The second full line on the right-hand page says "bee in rocite sh" and then the "ip" wraps around above it. ("Be in rocket ship"). I think he takes the possibility of silent "e" a little too seriously. The third line down is "in altr spas" ("in outer space"). The rest I’m not so sure about.