Here's the part that's hard to hear but important to understand:
Every day your child spends learning letters on a screen instead of writing them with a pencil is a day the reading foundation isn't being built. The brain-imaging research is unambiguous about this. The Elsevier study confirmed it. The systematic review quantified it.
Screen time isn't neutral. It's a trade-off. And the trade-off has a cost that compounds every week.
The window for building writing fluency most easily is between ages 3 and 8. During this period, the brain is actively constructing the neural architecture for literacy. After age 12, that window narrows. After 14, building what should have been automatic becomes dramatically harder.
Right now, the average American preschooler gets about 2 minutes of actual writing practice per day. The rest of their "learning time" is often spent on screens that train recognition but don't build formation.
The countries that consistently produce the world's strongest readers and writers — Singapore, Japan, South Korea — don't use apps for letter learning. They use pencils. 30 to 40 minutes a day. They score 12 to 39 points above the U.S. on every international reading assessment.