From the word in-born, this is a type of talent that an individual was born with

Yes as the word in-born defines it, surely a talent which is maybe a human grow up & learn through culture, or environment of all around, as a kid.

the person has the voice already whereas playing football can be seen as a self-learned

All right, well said. There is a huge difference between bother of examples, as it was to differentiate bot of talent forms. Amazing.

I'm a very good teacher who has also undergone a series of training.

It is good to know that your inner talent is about teaching & training. The society needs these types of teachers who think they can be teach, and they are confident about their passion. So it will help others in good ways. We have seen teachers who are good at their education, but don't know the art of teaching. So it causes difficulties for students.
Good, post. Wishing you Success.