A few years ago, a woman I was talking to said that she didn't agree with the use of the word disabled when describing someone with a disability. Her preference? Differently-abled. Not only I was taken aback by her comment because this is the pronoun I (and many disabled people) choose to use, but I was bothered that this opinion came from an able-bodied person. Also, I don't like that she preferred using a phrase that emphasizes different.
To me, calling myself disabled is no different than using gender pronouns (i.e. his, her, he, she, etc.). If I prefer using a particular pronoun to describe myself I don't believe anyone has the right to question it.
When I was little, it was common to use the word handicap when referring to a person with a disability, but much like the word crippled before it, handicap is no longer politically correct to say due to its negative connotation. Like crippled, when I hear the word handicapped it makes me feel like the emphasis is on what I cannot do and can lead to the assumption that I have a cognitive disability, whereas if I say "physical disability" it's much more specific. Depending on who I'm speaking to, I'll even just say I have a disability called Spina Bifida just so I'm clear with my language. I'll admit, there are times when I catch myself saying handicap like handicap parking. It's not great that I still say it, but like most people, I'm learning and trying to be conscious of my language.
I guess the reason why I don't have a problem with saying disabled or disability is that it's the word I personally want to use to describe myself. Nobody is putting these words in my mouth. Nor is it being used in a derogatory way. Therefore, in my mind, it's empowering, not negative. I'm sure there will be a point when describing someone as disabled will no longer be acceptable, but I'm personally okay with its use. Language is constantly evolving.
If you meet a disabled person and are unsure of what language to use, just ask them what their preference is. If they say they like using disabled or something else, accept it because it's their choice.