Isolate and pronounce the initial, medial vowel, and final sounds (phonemes) in three-phoneme (consonant-vowel-consonant, or CVC) words. (This does not include CVCs ending with /l/, /r/, or /x/.)

This standard is just like RF.K.2.C, but adds the nucleus, or vowel, to complicate things. For example, students should be able to take ten, pull it apart into /t/ /ɛ/ and /n/, and then be able to pronounce each sound separately. The exclusion of a few phonemes are due to the trickiness of liquids (liquid consonants, that is). Plus, the /x/ isn't even an English sound, so don't trip.