Suppose you want to describe to a friend the way in which a dog runs. You could just say:
.i lo gerku cu bajra
The dog does run. (".i" merely clarifies the beginning of a new sentence)
The dog runs.
This is totally accurate, but not very descriptive. Fortunately, Lojban allows you to connect gismu (root words) together in a way similar to adjectives and adverbs, but even easier. If you wanted to specify the color of the dog, you could modify the previous statement to say:
.i lo xekri gerku cu bajra
The black-type dog does run.
The black dog runs.
This is significantly more descriptive. Since combining words in this way to form an idea is so simple, order is important. Notice what happens if "black" and "dog" are reversed:
.i lo gerku xekri cu bajra
The dog-type black-thing does run.
The dog-like blackness runs.
The meaning has changed: the thing that is running is not necessarily a dog, but something black that is merely dog-like, insinuating that you don't really know what black thing it is that's running, but merely that it looks like a dog.
If you also wanted to comment on how the dog is running, you could use the same technique, as in:
.i lo xekri gerku cu sutra bajra
The black-type dog does quick-type run.
The black dog quickly runs.
.i lo xekri gerku cu mutce sutra bajra
The black-type dog does much-type quick-type run.
The black dog very quickly runs.
This kind of convenient word combination in Lojban is one of the reasons for the cmavo 'cu' (translated as "does"). Without we have:
.i lo xekri gerku mutce sutra bajra
The black-type dog-type much-type fast-type run-thing.
In other words, Lojban word rules turn the statement into a long compound noun, while adding a 'cu' separates the ideas into a valid statement.