People have always communicated(交流)with 1 ．In the past when they couldn’t write, they used simple symbols(记号)to send their message．Some groups of North America Indians were experts 2 messages．For example, a small stone on top of a large one meant “This is the way．”If there was another small stone on the right, it meant “Turn right．”Some grass with a knot(结)meant “Danger” 3 ．
Maybe you know that in the forests of Africa, it 4 to travel from village．But drum(鼓) 5 from many kilometers away．So, some groups of Africans made their drums 6 like people．
The Incas(印加人)of South America used to send messages by typing knots in a rope．Messages have been found, but 7 can understand 8 they mean．And the Egyptians used pictures as a kind of 9 but only 10 people 11 to understand them．
Today, we also use 12 ．When we are in a car and we see a red light, we stop the car．When a mother says to her child,“Eat your cake!” the child eats the cake sometimes．The red light and the words of the mother are 13 ．And it is a 14 that the basic means of communication between people is, of course, sounds．
Maybe you know that there are more than 3000 languages in the world today．And about 13 of 15 are spoken by large groups of people．Languages of the world are both similar(相似) 16 different．They are similar because we can talk and write about the same things and they are different because we talk and write about these things in 17 ways and we use different 18 ．
It is 19 that we have to learn a second language 20 communicate with people who do not speak our language．
