I agree with most of the posters here the teacher/school your child attends can possibly be a negative to early learning. I have done EL with all of my children and my oldest is now 10. The Only thing negative I have experienced was when my oldest went to kindergarten. My daughter was really bored with the work (because we had covered most of that 2 years before at home) and was talking/disrupting too much in class.
The teacher did not believe my daughter could read at the beginning. At the end of October (they started school in the middle of August) the teacher finally decided to test her during a parent teacher conference, my daughter blew her away by reading at the 2nd grade level. The class was on their 4th letter and my daughter was reading chapter books!
I thought well now that she knows my daughter can read at a higher level things would be easier right? Nope, I was completely wrong. Things actually got so much worse. The teacher refused to make any changes to my daughters school work. She said that she had to stick with the curriculum. I even offered to send challenging worksheets to school so that they could just hand to my daughter when she was done with her work. They (the teacher and the principle, yep I went all the way up to the principle but got no luck) said they couldn't do that either.
By January my daughter was bored out of her mind and didn't want to go to school anymore. She was so frustrated she stopped doing reading at school all together. They took a special reading test on the computer and she failed it because she didn't even try. At this point the teacher actually told me that I needed to stop reading with her at home!!!! I could not believe my ears. Apparently my daughter told her she only wanted to read at home not at school because it was boring at school. Hello!!! If that doesn't tell you, that you need to give more challenging work then I don't know what does.
The teacher said that if she didn't pass the second computer test in May she would fail kindergarten. I asked her if she was serious. Why on earth would they fail a child from kindergarten when they knew that child could not only read at a second grade level but add, subtract, and skip count? She said there was nothing she could do if she failed the reading test she failed kindergarten, even if they already knew she could read. >
I didn't want my daughter to fail so I stopped reading with her. I mean really, how could I let her fail kindergarten? That was the biggest mistake of my life. I truly wish I could go back in time and remove my daughter from that school right then and there. The rest of the school year was horrific my daughter cried, pleaded, and begged me not to send her to school every morning. It was heartbreaking, but the worst part of it all, she went from loving reading to hating it.
In the end she passed their computerized reading test and kindergarten. But she lost so much. I took her out of that school at the end of that year. It was so traumatic for her she didn't want anything to do with school. I decided to give her a break and homeschool. I am so glad that I did. I wasn’t sure if that was the right decision but I figured she learned so little at school and so much at home that I couldn't possibly do any worse. It took a year just to detox. She really didn't gain much that first year after kindergarten and still hated reading. The second year went much better and she learned so much. Pretty much every year since has been great. Now that I have 2 little ones that can read I will not be putting them in school.
It is really heartbreaking to watch a child’s love of learning squashed. Especially after spending all of your time and effort to grow and foster a love of learning.
What I can tell you is that if you do EL and are planning on sending them to school, just make sure it is a school that will work at your child’s level and not just stick to the curriculum. Research the school as much as possible and don't just trust the schools word, try to seek out parents of children who are advanced for their age and ask them as many questions as you can. I did research before I put my daughter in her school. They said they were able to accommodate her but in the end they obviously weren't willing to.
Ok end rant...
As far as EL damaging the child in any way I really can't think of any. I did early reading and math with all of my kids and haven't experienced anything that hurt them intellectually, emotionally, or in any way. My 10 year old is still advanced for her age and has a large vocabulary. She will often talk to adults and there have been times where she had to explain what a word meant (to the surprise of the adult). The adult will usually turn to me and give me a questioning look and I will usually say that she is right.