Image by panshipanshi on Flickr. CC BY-NC-SA 2.0.

Salvadoran Jaime Vázquez Villalta explains in this article the appropriate ways to talk to people who have a disability:

Al dirigirse a un familiar, amigo o conocido que presenta algún tipo de discapacidad, en primera instancia debemos asumirlo como una persona, con virtudes, talentos, fortalezas y debilidades, pero ante todo, como una persona porque eso es, un ser humano que forma parte de la sociedad.

When you talk to a relative, friend or acquaintance that has some kind of disability, in the first place we should treat them as an individual, with virtues, talents, strengths and weaknesses, but above all, as a person because that's what they are, a human being that is part of society.

The author, who uses a wheelchair, has the goal of educating other people on his blog Desde mi silla (From my wheelchair) to create a more equal society.