It isn't a complete answer, but notice that in English we, too, make new words by combining two existing words. These are called "compound words." Often they start out with a hyphen joining the two words--"half-time," and then gradually people will think of it more and more as a single word and drop the hyphen, "halftime." There are hundreds of them. Here are just a few:
airfield, blackberry, doughnut, earthquake, fireworks, headache, honeybee, moonlight, raincoat, stockbroker, toothpaste, wastebasket, wavelength.