Accents are caused by “interference” from your first language. All languages have certain ways their sound is made; there is a unique combination of tongue movement, lip movement, jaw movement, and vocal chord movement for every sound in every language. And languages are spoken from different parts of the mouth than others. In addition, what makes a pleasant voice or sound is different for each language. So we bring these rules from our first language to the new one we are trying to master. And sometimes it doesn’t work. Sometimes these rules result in sounds that don’t belong in the new language. And sometimes these rules result in our inability to hear or imitate sounds in the newer language. All this is called “interference”. If you are an adult, it is often helpful to understand intellectually what is going on; it makes it easier to make the physical changes necessary to sound better in language #2.
All languages have sound systems, pitch ranges, and rhythm and intonation patterns. We just don’t all use the same ones! There’s a lot to learn in another language, but the last learning curve for adults is often the “sound” of the other language, the “song” of the language, its pronunciation and intonation.
I’ve created pages for the languages that I work with most frequently. I hope they help you understand what might be causing some of your interference problems.