Helena Curtain's, (Associate Professor Emerita at the University of Wisconsin-Milwaukee) collection:
"The sum of human wisdom is not contained in any one language."
Ezra Pound, in the ABC of Reading
"The direction in which education starts a man will determine his future life."
Plato (427 BC-347 BC)
"Decisions that are made about what will be accessible to children help shape the kinds of minds they will come to own."
Elliott Eisner
"Through learning language, we learn about culture.
Through learning about culture, we learn respect for others.
Through learning respect for others, we can hope for peace."
"A rose, maybe, is a rose, but it is not une rose, is not eine Rose, but multiple ways of viewing and talking about roses."
Claire Kramsch, Context and Culture in Language Teaching,
Oxford University Press, 1993. (p.2)
"Give your mind a chance to travel through foreign languages."
Neil Simon
"Die Sprache eines Volkes ist seine Seele." ("The language of a people is its soul.")
Fichte
"Our linguistic and cultural myopia is losing us friends, business and respect in the world." J. William Fulbright
"El que habla dos lenguas vale por dos."
("The person who speaks two languages is worth two.")
Spanish quote
"When I speak Polish now, it is infiltrated, permeated, and inflected with English in my head. Each language modifies the other, crossbreeds with it, fertilizes it. Each language makes the other relative. Like everybody, I am the sum of my languages."
Eva Hoffman, Editor of the New York Times Book Review
Reprinted with permission from ACTFL Newsletter, Winter 1991.
"One free lunch in the world is to learn another language in early childhood."
Stephen Pinker, The Language Instinct
"Language is a tool for overcoming powerlessness. Our professional commitment intrinsically drives us to help the inhabitants of this planet to communicate with each other and to negotiate the meaning of peace, of goodwill, and of survival on this tender, fragile globe."
H. Douglas Brown (TESOL at Twenty-Five: What are the Issues? TESOL Quarterly,
V. 25 No. 2, Summer 1991.)
"Learning to speak another's language means taking one's place in the human community. It means reaching out to others across cultural and linguistic boundaries. Language is far more than a system to be explained. It is our most important link to the world around us. Language is culture in motion. It is people interacting with people."
Sandra Savignon Communicative Competence: Theory and Classroom Practice.
Reading, MA Addison Wesley, 1983, p. 187 .
"Language is not a genetic gift, it is a social gift. Learning a new language is becoming a member of the club -- the community of speakers of that language."
Frank Smith
"You can't see other people's point of view when you have only one language."
Frank Smith
"When you know another language, you suddenly realize there is a multitude of worlds. You can become a member of EVERY club."
Frank Smith
"One language sets you in a corridor for life. Two languages open every door along the way."
Frank Smith
"Bilingualism is diversity, tolerance, understanding, richness, power ... celebration."
Notes from Talk at California Association of Bilingual Education Conference,
February 2, 1994
"I wish life was not so short," he thought. "Languages take such a time, and so do all the things one wants to know about."
J.R.R. Tolkien (1892-1973), English Professor & author of the "Hobbit,"
"Lord of the Rings"
"Internationalism does not mean the end of individual nations.
Orchestras don't mean the end of violins."
Golda Meir (1898-1978), Israel's third prime minister
"The real voyage of discovery consists not in seeing new lands but in seeing with new eyes."
Marcel Proust (1871-1922), French novelist
"For men and women are not only themselves; they are also the region in which they were born, the city, apartment or farm in which they learned to walk, the games they played as children, the old wives' tales they overheard, the food they ate, the schools they attended, the sports they followed, the poems they read and the God they believe."
W. Somerset Maugham (1874-1965), English novelist, playwright, short-story writer
"Many people with different backgrounds, cultures, languages, and creeds combine to make a nation. But that nation is greater than the sum total of the individual skills and talents of its people. Something more grows out of their unity than can be calculated by adding the assets of individual contributions. That intangible additional quantity is often due to the differences which make the texture of the nation rich. Therefore, we must never wipe out or deride the differences amongst us — for where there is no difference, there is only indifference."
Louis Nizer (1902-1994), American lawyer, author, speaker, born in London
"Language embodies the world view of a culture and is unique to the culture that created it. It reflects values and concepts that are deemed to be the most important by a culture. A language describes the culture it comes from."
Noam Chomsky (1928 - ), professor of linguistics
at the Massachusetts Institute of Technology,
social/political theorist, writer, born in Philadelphia, Pennsylvania
"Learning a foreign language not only reveals how other societies think and feel, what they have experienced and value, and how they express themselves, it also provides a cultural mirror in which we can more clearly see out own society."
Chancellor Edward Lee Gorsuch, chancellor of the University of Alaska, Anchorage
(retired in 1994), member of the Arctic Research Commission
"Americans who travel abroad for the first time are often shocked to discover that, despite all the progress that has been made in the last 30 years, many foreign people still speak in foreign languages."
David Barry (1947- ), American writer and humorist
"If we spoke a different language, we would perceive a somewhat different world."
Ludwig Wittgenstein (1889-1951), Austrian philospher
Other collected quotes:
“A monolingual child is an underprivileged child.”
“If you talk to a man in a language he understands, that goes to his head. If you talk to him in his own language, that goes to his heart.”
Nelson Mandela
“I do not want my house to be walled in on all sides and my windows to be stuffed. I want the cultures of all lands to be blown about my house as freely as possible. But I refuse to be blown off my feet by any.”
Mahatma Gandhi
“To have another language is to posses a second soul.”
Charlemagne
"Language exerts hidden power, like a moon on the tides."
Rita Mae Brown, Starting From Scratch, 1988, US author and social activist
"Own only what you can carry with you; know language, know countries, know people. Let your memory be your travel bag."
Alexander Solzhenitsyn, Russian author & dissident in US (1918 - )
"A different language is a different vision of life."
Federico Fellini, Italian movie director (1920 -1993)
"Language is the road map of a culture. It tells you where its people come from and where they are going."
Rita Mae Brown (1944 - ____) US writer, playwright
"Never impose your language on people you wish to reach. "
Abbie Hoffman (1936 - ____) US political activist
"No man should travel until he has learned the language of the country he visits. Otherwise he voluntarily makes himself a great baby-so helpless and so ridiculous."
Ralph Waldo Emerson (1803 - 1882) US philosopher, poet, essayist
"A man who does not know a foreign language is ignorant of his own."
Johann Wolfgang von Goethe (1749-1832), German writer, scientist,
master of poetry, drama and novel
"I live in a small house, but my window looks out on a large world.”
Confucius (contributed by Janet Robles)
"Any tool has multiple uses. Language, for example, can be either a bridge or a barrier."
Shane Tourtellotte in String of Pearls, a science fiction story from Analog, 7/8 2006
“Children are like wet cement. Whatever falls on them makes an impression.”
"While you are divided from us by geographical lines, which are imaginary, and by a language which is not the same, you have not come to an alien people or land. In the realm of the heart,
in the domain of the mind, there are no geographical lines dividing the nations."

Anna Howard Shaw
The above URL has quotes for languages other than English as well.
"...know languages, know countries, know people."

Aleksandr Solzhenitsyn
“Language shapes the way we think, and determines what we can think about.”

Benjamin Lee Whorf
"It is of interest to note that while some dolphins are reported to have learned English - up to fifty words used in correct context - no human being has been reported to have learned dolphinese."

Carl Sagan
"Those who know no foreign language know nothing of their mother tongue."

Johann Wolfgang von Goethe
"You should know at least three languages .... think and dream in at least three languages...""
Bedri Rahmi ~ Turkish poet & artist ~ 1913 - 1975
(contributed by Aysegul Acar-Dreyer)
(Can you contribute a favorite? Please e-mail me.)