It is much easier to teach yourself a foreign language in the 21st century considering all that is instantly available on the Internet. Yet, there are many ways to learn and some are more enjoyable and efficient than others. However, the wealth of resources available today is overwhelming and this is why a teacher can help you choose the appropriate material, show you interesting ways to interact with it and suggest a correct sequence of study which is suitable to your learning style and motivation.

Moreover, even if you're very successful at exploiting existing resources languge fluency is only really attainable by spontaneus practice with a native speaker.