According to a presentation I went to today, some people seem to have an innate talent for languages, especially for acquiring a native or near-native ability to pronounce foreign languages. This doesn’t mean that people who lack this talent or only have it to some extent can’t learn languages, but only that they will probably speak them with a foreign accent. There are people who can read, write and understand foreign languages at a native level, but who speak them with a strong foreign accent. This phenomenon is called the ‘Joseph Conrad Effect’ after the famous author who wrote in impeccable English but spoke it with a strong Polish accent.
Learning to speak a foreign language without any trace of a foreign accent is very difficult and few adults manage to do so, with the exception of some people with a talent for languages, and children, who seem to be very good at acquiring native pronunciation of foreign languages
Pronunciation is not just about pronouncing individual sounds and words, but also learn the intonation, pitch, rhythm and stress patterns. English speakers use quite a wide pitch range, or in other words their voices can do up and down quite a lot. In contrast German speakers tend to have a narrower pitch range and some things in English that would involve your voice going up or down quite a lot might be indicated in other ways in German.
Extensive listening to the language you’re learning can help you to learn how to understand and pronounce them accurately. It also helps it you learn about phonetics and phonology, as then you’ll know what to do with your tongue, teeth, lips, etc. when pronouncing various sounds.