I have put my son to preschool when he was 1.8 yrs now he is 4 yrs old. He is not recognizing the alphabet and numbers. He is fast in writing. He writes the alphabet and numbers but doesn't recognize them... He is good in all the other activity.... We tried all possibility but not successful... his teacher also finds the same problem... I really don't know what to do.... please help me...
What a child can do at this age varies a lot. If you read forums, you'll see mothers telling of their 4 yr. olds who can read. That's not the norm. Does his preschool teacher think he's behind the other kids, or is he average? At 4, he should be able to: recite the alphabet, count, enjoy listening to you read, understand that print carries a message, be able to identify familiar signs (e.g. a store or restaurant logo he sees often) and labels (cereal box, etc.). So you see, he’s probably where he should be. I'll address letters, but the same goes for numbers.
While I don’t know exactly what age your son is, I wouldn't worry too much about it. I would work on it at home, because it will help him if he can read by the middle of first grade. (I didn't even try to teach my kids to read until kindergarten. I did use a phonics and phonemes program. They're all avid readers now.)
According to the US Department of Education, most kindergartners are able to: ‘pretend’ to read, retell simple stories, recognize letters and letter-sound matches, show familiarity with rhyming and beginning sounds, understand that print is read left-to-right and top-to-bottom, begin to match spoken words with written ones, begin to write letters of the alphabet and some words they use and hear often, and begin to write stories with some readable parts. So aim for this.
One of the most helpful ways to teach your child to read is through phonics and the identification of phonemes - simple letter blends like go, see and at. But to do this, you need to know about phonemic awareness. You can do this when you read, but also as you are talk to your child. (“I like these socks. Sssssocksss. The ’s’ makes a ’ssss’ sound.” When you read, do it for some words, concentrating on only a few letters at a time, showing him the letters.)
You can try this for six months and see if he starts picking it up. If he does, great! He’s on his way. If he shows no response, talk with a speech and language therapist. For children with any kind of disability or learning problem, the sooner they can get the special help they need, the easier it will be for them to learn.
Below are some resources, some are guidelines, some are things you can do, some are heavier reading. These are for children in the US. If you live elsewhere, your country will have similar sites.
Hopefully you'll get answers from other parents with other tips and insights.
Typical Language Accomplishments for Children, Birth to Age 6 -- Helping Your Child Become a Reader
Tips for Teaching Your Child About Phonemes
Report of the National Reading Panel
Learning Disabilities, Dyslexia, and Vision
Four years old is still early. Kids have to hit a certain developmental milestone in order to perceive oblique lines on letters like 'K'. They can be trained to perform things like writing without really understanding it completely. This article explains a little about the difference between learning and training in this situation.
In other words, it's perfectly normal and you wouldn't even notice if you weren't rushing it a little. Just relax and wait for him to be ready.
As he continues to read letters and numbers, he will (barring certain learning disabilities) eventually learn to recognize them as well, which is needed for reading.
Have you tried practicing pronouncing them with him? I.e. you hold up a card with the word "dog", and have him say it? By pronouncing each letter separately, he might learn to recognize them by assigning sounds to them.
EDIT: Another option would be to try and have him practice copying text. That way, he'll have to copy individual letters. If, as you say, he can write them, he will be doing so, but "on command" so to speak, as he is reading them first.