Hi Carlos, thanks for engaging. Of course, it's a strong claim to say that language completely defines one's reality. But it does some sense shape how we perceive our world. I think when philosophers say "language," they don't mean "language" as a mere collage of words but also how its usage corresponds to a certain reality. They also refer to the its cultural significance.
For instance, it's considered rude to address our elders and superiors by our first name in my country. We use honorific terms "uncle" and "aunty" to address strangers who're seemingly older than us. On an unconscious level, we've created a social hierarchy. And it reflects in how we use language.