As an example of the difficulty of the case system in German, take the rather artificial sentence, typical of the grammar books from which I learned the language at school: The young man gave a red rose to the pretty girl. To translate this correctly into German, you have to know the gender of the 3 nouns (including the fact that girl (M�dchen) is not a feminine but a neuter noun!). You must determine that man is in the nominative case, girl in the dative case and rose in the accusative case. From this you can then work out the correct form of the articles and the necessary adjective endings. You also have to know that in sentences containing a direct and indirect object (both of which are nouns), the indirect object must come first. Put all this together and you have the sentence:
Der junge Mann schenkte dem h�bschen M�dchen eine rote Rose.
The learner of English most certainly has an easier job in putting together sentences like this.