The DIBELS nonsense words are nothing like what HowlerKarma suggests. All the words have either CVC form, e.g. YOF WUB ZUC, or VC form, e.g. AJ EP IG. The test has 50 words (143 letters) and you read what you can in 1 minute. The nature of the test is clearly explained by the tester. Grade 2.1 is the last time it is administered.