The Nonsense word are very specifically assesses student's decoding abilities at their grade level. There are many benefits of using nonsense words. Some benefits are:
1) They provide an effective way for teachers to assess how well a student is applying the skills that are being taught in explicit phonics instruction. There are many tutors available that also provide decoding nonsense words assessment test facility for children.
Fluent decoding is the ability to quickly attach sound to written spelling patterns of the English language. When students memorize words as a whole, it is hard for a teacher to tell if they are relying on decoding strategies or memorization skills to read.
2) Practicing with nonsense words improves a student’s ability to ‘attack’ unknown or unfamiliar words in text.
How often have you seen a student just stop reading when they come to a word they don’t readily recognize? Students who have had practice decoding words that they clearly know are not real words, transfer the same word attack skills to real words.
These skills allow them to appropriately use the context of a sentence to figure out the meaning of unfamiliar words, rather than unsuccessfully over-relying on context to decode words.
3) They can be used to effectively teach syllabication
Many children experience a plateau with reading in third or fourth grade. Up until that point, they have been able to get by with memorization and guessing strategies. By third or fourth grade, more advanced work attack skills are needed. Multi-syllabic words require decoding many small "word parts" and putting them together.