Q. "Our little boy is in the second grade, very quiet and shy and lovable but lately he has been very sad too. Each day he comes home from school a little more depressed and he seldom wants to play with children his own age.

"I brought this up last week at the parent-teacher conference and the teacher was very defensive. She said he's in the slowest group but that he's doing all right; he gets many S's and he never causes trouble, she said. And then she threw me for a loop. She said maybe he was depressed because he didn't want to come home after school since I was so over-protecitive.

"I was still reeling from that when my parents came for Thanksgiving. My mother had brought Billy a new 'I Can Read' book and teasingly said he would have to read it to her before she would read it to him. This was a switch, since he makes us read a new book to him two or three times before he will tackle it.

"Finally he started to read and everything fell apart. He couldn't get anything right and cried and cried. That's when we realized that he did not know what the words were.

"Apparently he has been memorizing stories, but the ones at school are getting too long to remember and there aren't enough pictures to keep guessing. gI think that's why school keeps getting worse, but the teacher disagrees.

"I went in for an emergency meeting and she said that she was sure he could read or she wouldn't have given him an S in reading. She said my mother probably scared him because she was an unfamiliar person and because she and I expected too much.

"On the one hand I say to myself that she only has been a teacher for two years; on the other hand, I have to wonder.

"I'm convinced our son is smart -- he says such insightful things and he draws beautiful, beautiful pictures -- but he is different from other children. He's always been the one to get tired first, to be the clumsiest on the playground, and to act more immature than other children. It's so hard to get him to start a project and hard to get him to stop one, too.

"In school, his printing isn't too bad, but his words are always off to one corner of the page and his spelling is weird.

"I know I get more exasperated with him than I should, but could my attitude really make him act this way? Could it stop him from reading."

A. It's tempting for a young teacher to blame someone else when a child can't learn, which is why you need a better diagnosis.

Your child needs to be checked for learning diabilities, for he has some classic symptoms. Even if he didn't, it's one of the first things to be investigated when a child is unhappy in school.

One child in 10 needs some special tutoring and 1 in 20 needs special classes or even a special school. Almost all disabilities can be corrected or compensated for within 1-8 years, as the development of the brain catches up with the body.

These children are very slow to follow the step-by-step learning process that is automatic for most of us. This is what they must be taught before their self-esteem goes down the tube and before they are ready to read.

There are many disabilities which vary from child to child, and in combinations almost as individual as the children themselves.

The learning-disabled child -- usually a boy -- may be brilliant or retarded or average but like your son he generally is endearing and will cover up his problems in many ways -- so successfully that it can be hard for an untrained teacher to recognize.

A learning-disabled child may act withdrawn, like your child, or hyperactive or quite normal, but he probably will be socially immature and often clumsy, too, for he finds it difficult to know where he fits in either in time or space.

Until he does, school will range from hard to impossible, for everything involves these concepts. Indeed, all abstract ideas are hard for him to understand, which is why he must be taught in concrete terms.

Cause and effect is especially difficult and he won't use the word "because" as early as other children. Memory too, is shaky -- here today, gone tomorrow, and heaven knows where the next day.

In some cases the child can't register letters or will reverse them and numbers, too. All children confuse their b's and d's occasionally, but this child will have a pattern to this and all his learning quirks.

Other children may scramble the words they hear or read or pronounce or they may not be able to read because they don't track from left to right. Another child can't read from right to left, which makes it impossible to add or subtract a column of figures.

Or he may not be able to transfer words from one side of the page to the other -- because he can't integrate the two sides of his brain yet -- while another can't step backward or subtract or use past tense.

This may sound overwhelming, but the success rate with learning-disabled children is very high and most can go on to college.

Many of these facts and much of the hope is distilled, not from this mother's wisdom but from one of the best new books on the market: "No Easy Answers" by Sally L. Smith (Bantam; $3.95). It's a book of revelations.

The author, who founded the Kingsbury Lab School here so her learning-disabled child could go to school, tells you why these children don't learn and in the process you'll realize how children are supposed to learn. It should help any parent understand her schoolchild better.

There are chapters that can help any child -- with attitude as much as technique -- and specific advice, too, like the tests that can be given and how to use the new Public Law 94-142, which gives every child a right to be well-tested and to get "free and appropriate education" if he needs special help.

If you don't want to wait until the school can test your child and if you can afford the $490 charge, there is the Kinsbury Center, the venerable sponsor of the Lab School, at 2138 Bancroft Pl. NW. The center has a dozen diagnosticians who give the 4-5 hour individual tests and have more than 100 tutors who work with children in their homes or in schools or who teach adults at the center at night.

And if you're afraid the teacher will think you're over-protective, just remember: It's her job to teach your child; it's your job to protect him.

There are two other books worth noting this week, because they will be autographed on Saturday and would make great Christmas gifts.

Caldecott winner Peter Spier is signing his fine new children's book, "People" (Doubleday; $10) at the Cheshire Cat, 5512 Connecticut NW, from 10:30-1, and at the Book Castle in Gaithersburg, from 2:30-4.

The other book is "Oh Boy! Babies!" by Alison Gragin Herzig and Jane Lawrence Mali (Little, Brown, and Co., $5.95), which Jane Mali will autograph at the Book Castle from 11-1.