Which of the world's languages we acquire as our mother tongue is purely an accident of birth. If we grow up in an English-speaking country, then we will probably learn English. Alternatively, if we are born in Germany, Austria, Liechtenstein or the German-speaking part of Switzerland, then our first language is likely to be German. All children have the natural ability to learn any of the world's languages. Thus, a child has no more difficulty learning English or German than Mandarin Chinese. This is particularly true in terms of pronunciation – the sounds of one language are not inherently more difficult to produce than the sounds of another.

One of the things which happens as we grow older is that we lose the capacity to learn other languages with quite the same ease with which we acquired our mother tongue. In particular, this affects pronunciation. This is why it is often difficult to sound exactly like a native speaker, in other words, why we have a foreign accent. It is estimated that this innate capacity to learn another language begins to decline around the age of 12, although there is considerable variation from one individual to another. Clearly, some adults with ‘a good ear’ for languages do manage to achieve pronunciation which is very close to that of a native speaker, especially if they are living in a country where the language concerned is spoken on a daily basis.