(Assuming I understood your question, and you mean 'sparkling' as in a baby spark)
If I were to come across this without any context, I would probably read it as a verb or adjective (sparkling water, sparkling like a firework, etc).
However, using 'ling' as a diminutive isn't so rare that it can't be recognized - think fingerling potatoes, 'younglings' in Star Wars. I think it would be understood as a small spark if you provided the appropriate context.
"The sparkling flew into the air"
I would probably assume you missed the noun that 'sparkling' describes.
"Although still young, the sparkling left the nest to fly into the air with their elder brothers and sisters"
It's clear that 'sparkling' is a noun here.
(sorry about the weird examples)
You could also try spark-ling, or play with the format some other way, and see if that makes a difference.