The language primarily known for its use in developing Android applications is Java, although Kotlin has gained considerable popularity since becoming an official language for Android development. Java provides a robust platform for creating mobile apps, with extensive libraries and frameworks that simplify the process. Developers appreciate its versatility and large community support, which offer resources for solving various programming challenges. Kotlin, introduced by JetBrains, enhances Java's capabilities and allows for more concise and expressive code. Ultimately, both languages play a significant role in the Android ecosystem.