from the layer below it. The force of
gravity pulls the loose layer downward.
A lamprey (top) feeds on a rainbow trout.
BRITANNICA STUDENT ENCYCLOPEDIA Landslide 103
Landslides can be highly destructive.
They can bury or sweep away everything
in their path. They can block rivers or
cover entire towns.
A landslide needs a steep slope to get its
start. Rain, wind, waves, and other natural
processes can wear away the surface
of a slope. This wearing away, or erosion,
can make a slope too steep to support
the rocks and earth on top. Erosion
can also loosen or weaken the material
on a slope. This makes it easier for gravity
to pull the material down the slope.
Besides erosion, other forces can lead to
landslides. Rainstorms, melting snow,
and earthquakes can weaken the material
on a slope. Earthquakes, volcanoes,
and the use of construction equipment
or explosives can force material down a
slope.
Rockfalls, mudflows, and avalanches are
similar to landslides. A rockfall involves
large rocks falling from the top of a
slope or a cliff. A mudflow is a thick
stream of mud and other material that
moves quickly downward. An avalanche
is the sudden downward movement of
snow or other material.
#More to explore
Avalanche • Erosion • Gravity
Language
Language is a system that people use to
communicate, or share information.
Language includes speaking, writing,
and making gestures, or body movements.
Early human ancestors began
using spoken language several million
years ago. Humans began writing about
5,000 years ago. Language made it possible
for human societies to develop.
Humans are born with the ability to
understand language.Without any special
training, children learn to speak by
listening to other people’s speech. Other
forms of language, such as writing and
sign language, must be taught.
A landslide destroyed part of a town near
San Salvador, El Salvador, in 2001. An
earthquake caused the landslide.
Three girls use language to communicate.
Children usually begin to speak between
ages 1 and 2. They understand some language
even earlier.
104 Language BRITANNICA STUDENT ENCYCLOPEDIA
Building Blocks of Language
The most basic part of language is a
sound. Sounds can be combined into
words, words can be combined into
sentences, and so on.
Every language has several types of
words. The most basic types of words
are nouns and verbs. Nouns represent
people, places, things, and ideas. Verbs
describe action.
Every language has its own rules of
grammar as well. These rules control
the order of words in a sentence. The
order of the words gives the sentence
meaning.
Not all languages are spoken. In sign
language, hand movements stand for
letters, words, and sentences. Many
people who use spoken language also
communicate through gestures. For
example, in many countries, nodding
the head up and down means “yes.”
Languages of theWorld
There are thousands of languages
throughout the world. Some are spoken
by millions of people. Mandarin Chinese,
English, and Spanish are the most
widely spoken languages in the world.
Most countries have a standard, or official,
language so that citizens can understand
each other. Some countries have
more than one standard language.
Canada, for example, has two standard
languages: English and French.
Many languages are related. People who
study languages group related languages
together. English, German, and Swedish
belong to the Germanic group. French,
Spanish, and Italian are called Romance
languages. The Slavic language family of
eastern Europe includes Russian and
Polish. Chinese belongs to the Sino-
Tibetan language family of Asia.
How Language Changes
At times people need to speak with others
who do not know their language. For
example, Europeans who came to the
Americas hundreds of years ago needed
a way to speak with Native Americans.
Over time they began to use a simplified
mixture of their languages. These mixtures
are called pidgin languages. When
a pidgin language replaces the original
language of the group, it is called a creole
language.
A sign in the U.S. state of California says
“polling place” in seven languages. English
is at the top. Chinese, Japanese, and
Korean are on the left. Spanish, Tagalog,
and Vietnamese are on the right.
BRITANNICA STUDENT ENCYCLOPEDIA Language 105
Even people who share the same language
may develop different ways of
speaking. People in different parts of a
country may pronounce words differently
or use local expressions. These
varieties of the same language are called
dialects.
Languages often blur together. Countries
have borders, but languages and
dialects do not. One language may borrow
words from another language. Many
English speakers use such words as pajamas
(from Hindi), pasta (from Italian),
karate (from Japanese), and fiesta (from
Spanish).
Languages grow and change as people
use them. People often shorten existing
words. For example, “cellular phone”
was shortened to “cell phone.” Also,
people create new words all the time.
..More to explore
Communication • Grammar • Sign
Language • Sound • Speech •Writing
Lansing
Population
(2000 census)
119,128;
(2007 estimate)
114,947
