Lenguaje 9 años is a free Android game developed by The City of the Apps, designed to help children in the fourth grade develop their language skills. The game consists of more than 700 questions divided into 31 topics, covering everything from syllables and word stress to spelling rules and verb tenses.

The game is easy to play and has been specially designed to appeal to children. It is a fun and engaging way for kids to reinforce their knowledge of language, and it is completely free. The game is also available for use in the educational field, with permission granted by the developer.