One Question, Many Issues
You only asked one question, but, I see a number of issues here.
As I read your email, my concern is that I am not sure you know what your daughter's reading disability looks like objectively on paper.
Without test scores and the recommendations of a private sector evaluator, you will only be making assumptions about what she really needs.
A Section 504 Plan will accommodate your daughter's disability, but not necessarily do anything to remediate it.
For your daughter's English skills to improve, she must have reading instruction.
Unless she receives reading instruction, there is no reason to assume that her reading skills will improve. A second language will not be any easier in the future than it is now. Without a very solid base in English language, learning a second language will be difficult.
Latin is one of the base languages of English and is sometimes a good choice of a second language for a dyslexic student. If she has not had reading instruction after elementary school, that may not be the case. She may not be up to the point in English for the common elements in the two languages to be evident to her.
If your daughter has not had a reading evaluation lately, I suggest that you have one done now. Most colleges require an evaluation that is less than 2 years old (if she will ask for accommodations in college) so you will probably need to have another one done later in high school.
I suggest one now because her disability is interfering with her academics. You need to know as much as you can about her needs and abilities if you are going to make a good decision.
Finding an Evaluator
This is what the International Dyslexia Association (IDA) describes as an appropriate reading evaluation. Contact your state branch of the IDA to find an evaluator. You will also find evaluators listed in the Yellow Pages for Kids.
Understanding What Tests Mean and What They MeasureAn evaluation will give you a roadmap in planning for the future. The evaluation should identify your child's problems and include a plan to address these problems. You can learn how to track your child's progress or lack of progress. Read Understanding Tests and Measurements.
You really need to be sure from the evaluation what she needs.
Once you know that, you can see if a second language fits into that. You will also be sure whether or not she needs reading instruction. Her grades do not tell you that.
Get Advice from an Advocate or Attorney
If the evaluation shows that your daughter needs reading instruction to get her skills to grade level, you may need an advocate or attorney to advise you and to get the services soon enough to be of value.
These are directories of advocates and attorney that will be helpful.
Looking Toward the Future
These resources will help you and your daughter prepare for college.
Documenting a disability and requesting accommodations on the SAT.
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