Ask questions or just talk about different languages. Since BrainKing is an international game site supporting many languages, this board can be kind of useful.
King Reza: Yes, young children often make such mistakes. And it's not always a regular form that is used in place of the correct irregular form. When I was in grade school, some of the other children used to use "brang" rather than "brought" as the past tense of "bring", following the pattern of ring, rang, rung; sing, sang, sung; sink, sank, sunk; etc.