Performing in your own language can be a feat of sheer luck, but if you're not lucky enough to have a native tongue, it's not impossible to learn how to write in your own language. But don't expect to become a lyricist overnight. It takes time and practice.
The best way to start out is to study your favorite songs, analyze their lyrics, and then use that knowledge to write a song of your own. The process isn't as difficult as it might seem, as long as you're willing to put in the effort.
Among the many things to do while writing a song is to study the song's structure. This will help you know which parts to highlight. Also, be sure to incorporate your favorite melodies into your own song. This will make the writing process a whole lot more fun.
It's also a good idea to take note of your favorite musicians' style. If they have an interesting writing style, you'll be able to incorporate some of their idiosyncrasies into your own song. You can do the same with instrumental pieces.
For instance, if you're a guitar player, consider using the reverb and twang on your own instrument. This will help you achieve the most out of your songs.
The best songs are created by artists who adapt their craft to their own musical tastes. They can do this by composing song texts on their own or by using a text generator.