Here's why:
* Languages are learned, not innate: Humans are not born speaking a specific language. We learn language from our environment, primarily from our parents and caregivers.
* Multiple languages exist: Thousands of languages exist around the world, each with its own unique history and development.
* Language development is gradual: Children don't suddenly start speaking a complete language. They go through stages of babbling, single words, and eventually phrases and sentences.
So, instead of a "first language," we talk about:
* Native language: The language a person is exposed to and learns from birth.
* First language acquisition: The process by which children learn their first language.
It's important to remember that language is a complex and fascinating phenomenon that has evolved over thousands of years. There's no one "first" language, but rather a rich tapestry of human communication.