Because would be boring without them :)

There is a biblical account in Genesis 11:1-9 that tells that at one time the whole earth spoke one language. The people decided to build a high tower and make a name for themselves. They used brick and mortar, and started their grand high-rise, but God was not pleased with their motive. As a result, God confused their language, causing them to speak different languages so they would not understand each other. By doing this, God thwarted their plans. He also scattered the people of the city all over the face of the earth. From that time on, there has continued to be an evolvement of the languages. This tower is known as the Tower of Babel.

Its due to the constant migration and dispersion of groups of people over time, eg the Celts from central Europe brought their language to Western Europe, settled in different areas and developed variants of the same language and over centuries became quite different in sound, but very much still related. Same for Spain and Portugal with Spanish being a Romantic language and related to Portuguese, Romanian ,French etc.

Ciao Luchito! Different people settled in different places in the world so they communicated in different ways... and voila many languages!

i think in my openion a long time ago when the people lived alone n did not discover transport yet and maybe didnt even know about other people existing that when they started there own communication words and traditions and then they started going n traveling and exploringn n then globalization came n now we know every thing