A split is what we call it when a bird needs two copies of the gene (one received from each parent) in order to be visual for a mutation, but this bird has only one copy of the gene. This bird will not be visual for the mutation, but if it's paired with the right mate it can have children who are visual.
Pearl pied means that your bird is visual for two mutations - pearl and pied. If he's male, he got both genes from both parents, and we know for sure that mom had to be visual pearl. His dad could have been either visual or split to pearl, and both parents could have been either visual or split to pied. Your bird is not split for either one of those mutations because he's got two copies of both genes not one. But he could be split to something else, like whiteface, cinnamon or lutino. If he's split to one of those mutations you won't see it on him, but if he had children you might see it on them.