There is a reason your child's writing struggles are not improving with time. And it is not effort, intelligence, or attitude.
Writing is a dual-task skill. To write a sentence, a child must simultaneously manage the physical act of writing — letter formation, spacing, pencil control — and the cognitive act of composing — choosing words, building structure, organizing ideas. When both of those tasks are conscious, the brain runs out of bandwidth. The child cannot think about what to say because they are still thinking about how to write.
In children who have automated the physical layer through structured practice, handwriting is invisible. Their hand moves without thought. All their cognitive energy goes to ideas, vocabulary, and structure. These are the children who finish assignments quickly. Who write with confidence. Who look like "natural writers."
They are not natural writers. They are children whose mechanical layer was built first.
Your child is trying to do both at the same time. Every assignment is twice as hard for them as it is for the child next to them. Not because they are less intelligent — often these children are more intelligent — but because their brain is splitting its resources between two demands that should not both be conscious at once.
And here is why the gap widens: the child who can already write fluently gets more practice at composing. Every assignment makes their writing better. The child who is still struggling with mechanics gets less effective practice from the same assignment, because their cognitive energy is consumed before they reach the thinking part. Same classroom, same teacher, same homework — radically different outcomes.
This is called the Matthew Effect in literacy research. The children who have the foundation get more from every hour of instruction. The children who lack it fall further behind with every passing week, even while doing the same work.