Deeply exploring a second language for the first time often leads learners to question why the language they're acquiring doesn't match up neatly with their first language. I have had students throw a fit about such challenges as syntax and gender. For English speakers, the idea of nouns having to be feminine or masculine can be daunting and even confusing. Students ask why are some of the body parts on a female body not feminine nouns. If it's a woman's breast, why is it "el pecho"? Or, how can there be two words in Spanish for ideas that only have one word in English; for example, how can Spanish have words like "anaranjado" and "naranja" that both mean "orange"--isn't that confusing? How can the words "there is" or "there are" in English get translated into just one short word, "hay", in Spanish? Why does the verb "gustar" work backwards from the way "to like" works in English, so that we say "me gusta el queso" and literally mean "cheese is pleasing to me"; and why does it have romantic associations to say that a certain person "me gusta" when in English we can say "I like so-and-so" in an entirely platonic way?
We cannot get inside the mind of the anonymous "founders" of a language, any more than we can get inside the head of our favorite author to know "why did s/he say that?" and "what did s/he mean?" Scholars puzzle over these questions while knowing that the real answer will always evade us. We wonder, how many people does it take to get a new language system up and running? Where will our language take us in the centuries to come? We can look toward the past, and must respect the fact that there is a future for the language(s) we speak that we may never know. Languages evolve over space and time, and they are influenced by such diverse effects as geography (what grows where the language is spoken? what are the weather, countryside and waterways like?), religion (what do the speakers fear? what or whom do they trust?), and economics (how do speakers earn money and spend it?)
Understanding that languages do not fit neatly over each other is an essential concept in language acquisition. The ultimate goal of learning language is to create a seamless fabric in the target language, so that thinking in, say, Spanish, becomes second nature. Having to translate every idea and every communication through a series of memorized equivalents weighs speaking and writing down. A small victory comes when a student can say, "Hmmm...I can't define it, but 'el arrullo'... has something to do with rocking a baby, or humming softly, or the sound the ocean makes." When you can feel your way through the language by instinct, you're starting to get a really good fit. Keep in mind that your favorite pair of jeans probably wasn't your favorite in the dressing room the day you bought them. Falling into a comfortable linguistic place takes time and patience. Savor the journey.