Note Humboldt's introduction of ''Weltanschauung''
Central to the Sapir-Whorf hypothesis is the idea of linguistic relativity: distinctions of meaning between related terms in a language are often arbitrary and particular to that language. Sapir and Whorf took this one step further by arguing that a person's whole world view is determined by the vocabulary and syntax available in his or her language.
The extreme ("Weltanschauung") version of this idea, that all mental function is constrained by language, can be disproved through personal experience: people in every language occasionally struggle to express their exact thoughts, feeling constrained by the language. It's common to say or write something, only to correct one's self or further clarify meaning, especially to someone being explained to. These show that ideas are not merely words, because one can imagine something without being able to express it in words.
The opposite extreme - that language does not influence thought at all - is also widely considered to be false. For example, it has been shown in studies that people's discrimination of similar colors can be influenced by their vocabulary for distinguishing said colors. Another study showed that deaf children of hearing parents are more likely to fail on some cognitive tasks unrelated to hearing, while deaf children of deaf parents succeed, due to parents being able to more extensively communicate. Computer programmers who know different programming languages often see the same problem in completely different ways.