First, let's examine what "ableism" and "ableist" mean. In short, skill awareness occurs when people are discriminated against or otherwise dehumanized because of a disability. This can include mental or physical disability. At the structural level, ability awareness also emerges with regard to literal access. Think of places where a wheelchair user cannot safely enter, a sidewalk that has not been properly built, or a classroom or live event that does not have a sign language interpreter. Ableism lives in our language too – even if we don't mean it that way.
What can that look like? For example, think about how often you use these words or phrases: crazy, lame, crippled, paralyzed, schizophrenic, bipolar, obsessive-compulsive disorder, compulsive, stupid, stupid, blind spot, blind reading, falling on deaf ears, moronic, insane or psycho. This list is also far from complete.
If you don't use these words yourself (well done!), You will likely find them frequently on social media, or even media in general. They are widely used and slang colloquial by most of the people, without the original harm and purpose behind the language. But that doesn't mean it's any less harmful, especially to people who live in marginalized conditions or who identify with some of these labels. Disability and mental health are already unfairly stigmatized – we don't need hurtful language that contributes to systemic barriers.
You may be wondering, well what can I say instead? Try to be more specific. For example, when you say that you are "paralyzed," you may be referring to feeling trapped, afraid of getting stuck, or so on. You can just say that you feel stuck. If you feel that someone's behavior is erratic or difficult to understand, instead of describing it as psychotic or ascribing it to a particular mental health condition, simply say so. People's conditions don't make them bad, angry, or distressing. When we divert speech from harm (even if it is unintentional harm), we take a small and steady step towards association and inclusion.