May I suggest you change the wording of "special needs" to people with disabilities, it has more impact and it covers anyone with any sort of disability. The term special needs has a tendency to set people with disabilities a part and different or not normal, and many people find the term offensive.
How long is your speech meant to be?
I think you don't have enough for even 5 minutes speech, but your topic is good. So I hope you don't mind I have changed your introduction, and you don't need to acknowledge everyone, a simple good morning everyone should be ok, unless you have special dignitaries present.
Introduction for speech
Good morning everyone, my name is ............... and my topic is Respecting people with disabilities, as I believe many people with disability are not being treated with respect & dignity as they should be.
Speech body;
We treat other people with respect and dignity, in a hope that people treat us the same. And people with disabilities should not be treated any differently. People with disabilities are people too, they think and feel the same things as you or I might, they also have the same rights as anyone else.
What is respect, respect is listening to others opinions, their thoughts and feelings, valuing them as whole person, regardless of any deficit they may have.
So how do we treat others with respect and dignity:
Most people with a disability are very capable of making choices and decisions for themselves.
We respect their right to express their thoughts & opinions, and we understand that their thoughts & opinions might be different to ours.
Be patient when working with a disabled person, it may take them a little longer to do some things.
Its ok to offer assistance, if someone looks like they might need help, but wait for a reply before trying to help.
When introducing someone with a disability we put the persons name first, not their disability, in fact don't even mention the persons disability.
Don't make assumptions about a person, just because someone is in a wheel chair does not mean they cannot communicate.
Don't speak to them as if they are a child.
Don't talk to loudly, their not deaf.
Don't talk slowly, talk the same way you would anyone else.
Conclusion
People with disabilities are first and foremost a human being, who has a legal right to be treated with respect and dignity at all times.
Quote "Our inner strengths, experiences, and truths cannot be lost, destroyed, or taken away. Every person has an inborn worth and can contribute to the human community. We all can treat one another with dignity and respect, provide opportunities to grow toward our fullest lives and help one another discover and develop our unique gifts. We each deserve this and we all can extend it to others." - Author Unknown
I have done many speeches over the years as a Youth & Disability support worker, and I usually try to find a suitable quote to finish off on. Also the wrong wording can ruin your speech. Many teachers are happy to read what you have put together, and may even correct wording for you.