Language is the use we make of sounds to name things and express ideas. Over time and with the movement of groups of people, these names have diverged and language has become more complex to incorporate abstract concepts.
Culture is how the community we live in behaves towards each other both within the family and in the wider world. Culture has come to have a wider meaning of appreciation of the arts. Each cultural group has developed a different way of expressing their community. West African masks and Mexican carvings are very different and reflect what those peoples want to express about themselves.
How we behave towards the members of our society is governed by custom - that's how it has always been done, and beliefs from whatever source - that's how it should be done.
Culture grows up in the environment we live in. Those who live in the rain forests of South America have evolved a way of life which suits the climatic conditions they live in and have to work in. The cultures of Northern Europe have evolved differently. Culture evolved from the need for survival and therefore how we behave with others of our species. The subtleties of that are controlled by a variety of factors such as environment and climate.
As a result of these diverse living conditions and belief systems, language has followed to express what is needed. Apparently Inuits have many words for snow and another group will have a wide range of words to express what needs to be dealt with precisely.
Communication is largely body language - watch cats and dogs how they communicate their feelings with great clarity without words. They have a culture'. We wonder sometimes why we react to someone positively or negatively yet if we look at their actions more closely we might have a clue. Desmond Morris (and others) wrote some excellent books on the subject.
Even how we express words in a spoken language mirrors the culture we live in. The Japanese have developed male and female languages within Japanese which perhaps demonstrate something of how their culture has evolved. Other communities have emphasised different aspects but have produced something unique.
When we first enter a community different from our own it is difficult to see how we should behave. What is polite? What is considered to be rude? The hand shake has become universal yet is unacceptable to some groups because it means touching someone of the opposite gender who is not family. What is considered courteous in one group is overlooked by another. Lack of understanding of another culture means we can offend while using the correct words. With the shrinking of the earth through modern communication it is interesting to see how we can communicate with those from other cultures in ways which are considered polite.
Culture preceded language.