"Julia is a child."
Translation:जूलिया एक बच्ची है।
That's a good question. Now ask it in Hindi but try not to use any unnecessary words ;) In some ways having two words that mean similar things is redundant, but isn't that always a feature (not a bug) of natural languages? They increase the expressive range of the language. In Hindi you get to choose between words with Arabic or Persian roots (ख़ूबसूरत) and different words, with the same meaning, that come from Sanskrit (सुंदर). You can use poetic words in songs that you wouldn't use in conversation, and so on. They do and they don't mean the same thing. But isn't the answer to your particular question "that's just the way is."?