The culture/language question is comparable in some ways to the eternal chicken/egg conundrum: perhaps if we knew that one came before the other, it would be easier to say how much one influenced the other. However, because it is fairly obvious that language and culture must have, to some extent, evolved together, each of the two has influences on the other.
Culture's influences on language and language's influences on culture are difficult to untwine: the proof of the mutual influences is available to us every time we speak, even if we do not always focus on it.
Some examples of how language may have influenced culture can be found that date back into early societies: the common misconception that the Innuit have hundreds of words for snow is false, but not unfounded. These people have several prefixes and suffixes that can be added to other words, so that four such suffixes can create a nearly infinite number of words for snow. This example, like another example where Native American tribal languages have many words for natural phenomena, is fairly obvious. However, there are also more recent examples of how language influences culture.
Subcultures have commonly used other versions of their own languages to distinguish themselves from the regular culture. An example is found in French, where the slang "verlan" involves vocabulary words spoken backwards. Many of these words are taken from Arab languages, such as "toubib," which in colloquial French means "doctor." Taking these words could be seen as simply a mix of two languages, comparable to the New York Puerto Rican Spanglish, however, in the French example, the teenagers speaking with these words have also assimilated some of the culture associated with Arab subgroups. Arabs in France are seen as a minority group and a general nuisance. It is to Arab groups that many of the suburban car burnings of the early 2000s were attributed to. However, we now know that it was this subculture that staged these revolts, acquiring not only the language but the assumed identity of the Arabic subculture in France.
Another example is in English: the subculture that emerged in the 50s, also known as the Beatnik movement, was, in its essence, influenced by language: the leaders of the movement were writers like Jack Kerouac and Allen Ginsberg. However, the subculture that emerged found a different sort of language to define itself. Similarly to the French "verlan" of today, the followers of the Beats took a marginalized minority, in this case, African Americans, and started using their words: "jive," "cool" and "crazy" are now associated with the younger generation, but they entered this vocabulary because of this cultural movement.
Language can influence culture in many ways. The existence or absence of a certain word or term from a language limits a people's ability to discuss the topic. The creation of new words paves the way for cultural renewal. Both culture and language are mutually influential, and with some examples, it is difficult to say which of the two did the influencing, however, it is prudent to say that there are thousands of examples of both in languages worldwide.