In chapters 4 and 5, we saw why it is useful to study the sounds of German if we want to pronounce words clearly and be sure that we are actually saying what we mean. This, however, is only one of the things we need to learn when acquiring a new language. All students of foreign languages are aware that, even with the best pronunciation in the world, they will not get very far if they do not know a fairly large number of words.

But what exactly is a word? This may seem like a rather strange question, since most people would probably claim to know the answer. Consider the following four definitions:

1. Words are pronounced separately.

2. Words are written with a space either side.

3. Words are units of meaning.

4. Words are units of grammar.

These are all perfectly acceptable suggestions. Yet, from a linguistic point of view, each is problematical.

The first answer suggests that words are somehow related to sounds, since their pronunciation occurs separately. But think of what it is like listening to a language you do not understand. Can you really tell where one word ends and another begins? Moreover, in chapter 5 on connected speech, we saw how the pronunciation of the same word may actually change due to the sounds of the words which precede or follow it. In conclusion, pronunciation would not appear to be a very reliable guide to the concept of word.