All children learn at different rates. While children naturally learn to walk and talk just by being around other people, alphabet recognition, as with all literacy skills, has to be consciously taught.
Does your daughter have pre-literacy skills, such as alphabet recognition? Is she completely unable to read or lacking in fluency or reading but not at grade level?
I am answering as if it is the first. If she has some literacy skills, please add information in the comments and I will come back and revise my answer to better suit your situation.
You do not mention if your child is enrolled in school, if you have made a conscious effort to teach literacy skills, if your child has been identified as having a learning disability, or if any pediatricians or educators have mentioned concerns in the past.
Certainly by age 15 I would hope that an adult (an educator or family member) would have made an effort to teach literacy and raised concerns if these efforts were unsuccessful.
If she is enrolled in school, by now the school should have evaluated her and developed an appropriate, individualized program.
At your daughter's age, I would recommend wasting no time in seeking out an evaluation and enrolling her in a literacy program.
I urge you to bring your concerns to your pediatrician and to your child's teacher, if she is enrolled in school. These professionals may recommend a specialist who will administer diagnostic tests and work with your child.
If you are in the United States, your child is entitled to a free and appropriate public education, including individualized support for diagnosed learning disabilities.
There are a number of reasons why a child may struggle with reading and many of them may be overcome with additional support. A diagnosis of a learning disability does not mean that your child will not eventually read at or above grade level.
Reading can open up entire worlds and I wish your daughter a great experience learning to read!
I am sorry to hear that your daughter cannot read. This must be really difficult for you and her.
It is best that you investigate the reasons why she cannot read so you can best help her.
Is your daughter having trouble identifying words with sounds?
Does she understand some words and not others?
Do you see her completing homework?
Is English her first language, or is she learning English for the first time?
Has your daughter been tested for a learning disability?
If you have not already, I suggest that you talk with your daughter’s school teachers. If you provide more information about your daughter, myself and others can provide you more specific feedback.
When you say she can't read, there are several things that come to mind. Can you be more specific? It could be a number of things. But I am thinking more in the phonics area. Unfortunately a lot of schools are now using a timed method for reading. This only increases anxiety and causes a block mentally with reading. When I pulled my child out of public school years ago, she would skip words to compensate for the "speed". However, speed is not as important as accuracy, phonics, and comprehension. My daughter can now read great! What you may have to do, is start from the ground up. Do some at-home tests and see how far she can go. You may even have to review phonics for her daily. Good Luck!
Whole Word and Sight Words continue to devastate young readers. (Google "40: Sight words -- The Big Stupid," if this idea is new.)
What to do? Start over, use phonics.
If child can read at all, test for Whole Word damage. Easy to do. If kids drop words, add words, substitute words, or reverse words, they are illiterate in the way that Whole Word generates. See site below for remedial help:
my sixteen year grandaughter cannot read she will say the word or spell a word and forgets the next second she speaks fluent english understands when asked a question acts like a normal teenager but a problem with reading she can copy off apage of any book has beautiful handwriting where can i get help her teacher says she will always be like this.
Even though I have never met such problem I person, it really seems to me that it has something to do with physiology. I mean she does see letters, so it should not be a problem to make syllables, and then words. But again, I am not familiar with this. I don’t understand…have you noticed it just now? Try to talk to her. Maybe she has a decent explanation about what strikes her about reading. She can end up getting online papers, you know. She needs to read.