This is a great question about nonsense words. In UFLI Foundations instruction, we use nonsense words mainly to help bridge connections between patterns in word chains. Dr. Holly Lane, UFLI’s director, has previously shared, “The research on the use of nonsense words is extremely thin. What little research there is suggests that nonsense words are either helpful or benign. I don't know of any research evidence that using them is a bad thing. However, there are decent theoretical arguments both for and against their use, so although we don't shy away from using them when they can be helpful, we don't make them a centerpiece of the program. If you're interested in exploring this further, here's a blog I wrote with Linda Diamond on this topic:

COLLABORATIVECLASSROOM.ORG

The Use of Pseudowords: The Importance of Being Earnest about the Science of Reading

 https://www.collaborativeclassroom.org/blog/pseudowords-reading-instruction/?fbclid=IwY2xjawQNRtlleHRuA2FlbQIxMABicmlkETJUaEpPdXBMREMzS00ycE9Cc3J0YwZhcHBfaWQQMjIyMDM5MTc4ODIwMDg5MgABHmi9SyP4uPtFrOCrCKqTK5r4-nkA6nA8hwXPedcIZJVodA_ebt9OcxqYbbK0_aem_XQHk6vxawbvs4HreOdpSZQ "

Dr. Colleen Pollett has previously shared about their purpose in assessment this way, “Any word (real or made up) is a nonsense word if you’ve never seen or heard it before. As kids learn to read, they will encounter lots of unfamiliar words that, to them, are nonsense words. For example, consider a 6-year-old child who can read words with consonant and short vowel sounds. This child would be able to read words like cat, bump, and spin which are likely familiar AND words like vat, zest, and bunt, which are likely unfamiliar.

When we are assessing children's phonics skills we need to know if they can use their knowledge of grapheme-phoneme correspondences to decode ANY word, not just recall words they're familiar with. So, another way to frame nonsense words is that you’re guaranteeing the word is unfamiliar. When we administer diagnostic assessments, the goal is to identify a student’s strengths and weaknesses so that we can give that student the targeted support they need. In other words, diagnostic assessment results give us the specific information we need to provide the best possible instruction and intervention for that student." Hopefully this helps!