I wonder if there is an adjective to describe orthography that deliberately aims for the kind of irregularity or defects one might find in a young child, but is a deliberate style, rather than an attempt to fake a child’s handwriting. The signature of the Spanish artist Miro comes to mind, although this question was actually provoked by the derivative design on a bottle of chianti (shown below). 

[![faux-infantile text][1]][1]

“Faux-infantile” is the best I can come up with myself. “Naïve” might fit the design. 


  [1]: https://i.sstatic.net/FAhkG.jpg