When Charles Berlitz was a child, each family member spoke to him in a different language: his mother in French, his father English, his grandfather German and his cousin and baby-sitters Spanish.

"My bedroom walls were lined with charts of animals and foods and parts of the world," recalls the linguist about growing up in the New York home dominated by his grandfather, language-teaching innovator Maximillian Berlitz.

"Each person would talk with me in their particular language and point to things on the charts asking 'What is this?' "

By the time he was 3, Berlitz, now 66, spoke four languages and was trying to make up one of his own.

"I didn't realize they were speaking different languages. I thought every person had their own particular way of speaking. Since I'd hear my mother switch to German when she spoke to my grandfather, I thought everyone had to learn everyone else's way of speaking to communicate. I wanted my own language, too."

Although his family dissuaded him from creating a new one, his grandfather (who spoke 58 languages) made sure that--from the age of 8 on--young Charles learned a different language every year. Today he speaks more than two dozen in varying degrees of fluency--"about 12 well enough to be interviewed in and about 15 more with the aid of a dictionary"--and is listed in People's Almanac as one of the 15 most eminent linguists in the world. (He has not been affiliated with the Berlitz Schools--now a subsidiary of Macmillan Inc.--since the late '60s.)

Language, says Berlitz, "is far more than different words used to communicate. It is a psychological outlook, an insight into the way people of another culture think."

An example is the Russian adjective--krasivaya or krasnaya--to describe a "beautiful" woman. Both are derived from krasniy, which means red.

"This has nothing to do with politics," says Berlitz. "Red has been a favorite color in Russia for many centuries. Coincidentally, it also happens to be a favorite in China where red is proverbially the color of joy, celebration and marriage, and white is associated with death and mourning."

Knowing just one language, he maintains, "is like living in a huge, wonderful house and never leaving one room. The force and excitement of learning a language is in discovering a whole new way of looking at the world. When we penetrate this different way of thinking, we have added another dimension to our own personalities."

Berlitz's own personality dimensions appear as varied as his linguistic skills. Besides directing language programs around the world and authoring more than 100 language books, he served as an Army counter-intelligence officer off and on for 26 years. His language proficiency saved his life several times and nearly exposed him once.

"I was posing as a waiter behind enemy lines, and a German officer read aloud something very funny. Since I wasn't supposed to know the language, I had to suppress a laugh. It was very difficult."

An underwater archeologist, Berlitz's great passion is exploring the mysteries of Atlantis and the Bermuda Triangle, the subject of his best-selling book which won the Dag Hammarskjold International Prize for Nonfiction in 1976.

"My interest in the origins of language led me to the study of civilizations before ours," says Berlitz, who now lives in Fort Lauderdale. He believes the Lost Continent was made up of "several islands in the southern part of the North Atlantic," covered by melting ice 11,000 years ago.

In response to skeptics' dismissal of his Bermuda Triangle book as "bunk," Berlitz rolls out a German proverb: "The only time I object is if someone makes a strong criticism whose mind is unclouded by the information."

Not surprisingly, Berlitz seems to have a foreign saying or anecdote for virtually everything. "Did you know," he asks, "that the lineal descendant of Dracula is working in Bucharest in a blood bank?"

Berlitz's storehouse of facts, anecdotes and trivia has been compiled into a fascinating compendium, Native Tongues (Grosset & Dunlap, 340 pp., $14.95), which touches on everything from "language incidents that changed history" to "insults and profanity around the world."

"I have tried," he says, "to write an overview of how language has affected the peoples of the world all through history, to deal with curious linguistic customs and give readers a glimpse of how our neighbors on Planet Earth think.

"People feel very strongly about their language. When conquerors have taken over another country, the last three things the conquered will give up--not necessarily in this order--are their religion, their cooking and their language."

The 2,796 languages and about 7,500 dialects in use, he notes, draw upon the 90 possible phonetic sounds humans can make.

One of the great mysteries, Berlitz acknowledges, "is why different peoples have produced different languages.

"It may be a question of climate. For some reason, people living on the seacoast in hot countries seem to speak fast and slur words together. People in the mountains usually tend to have a very measured, slower speech, maybe because they need more air."

Although Berlitz claims "anyone can learn to speak any language," he concedes that languages using clicks and tones are generally the hardest to learn since the inflections are subtle and often difficult to make.

Of all spoken languages still in use, he says Basque, a unique tongue spoken in northern Spain and southwestern France, may be the most difficult to learn.

"Basque is probably a remnant of a cave language spoken before the glaciers covered great parts of the Northern Hemisphere. Its extremely difficult structure and vocabulary have elicited the Spanish proverb: 'When God wished to punish the Devil, he condemned him for seven years to study Basque.' "

One of the easiest languages to learn, he says, is English, the second-most widely-spoken in the world. (Chinese is first.) "It English is pretty unisex--you don't have to learn male and female forms of nouns. Of all languages, Chinese is probably the most unisex in its pronouns having the same word for 'he,' 'she' and 'it.' "

The best way, of course, to learn a language is to live in that country. "If you can't," says Berlitz, "make friends or contacts who speak the language and try it out on them. Listen to tapes and tape yourself to hear how you sound."

It is "nonsense," he scoffs, "to assume you only can learn a language as a child. Children have an advantage in that they're very uninhibited and will reproduce exactly the sound they hear. So their accent tends to be very good. But adults have more points of reference in remembering vocabulary."

Politeness, claims Berlitz, is the key to success in a foreign language.

"Many language books are like a screech of complaining, teaching phrases like 'Waiter, my fork is bent!' It's hard to make friends that way. When you use polite words that indicate peaceful intentions, people are much more inclined to help. In most places--with the exception of Paris--people are delighted when you try to use their language."

Today's international traveler could get by in any country by learning "a rock-bottom basic eight-word vocabulary," says Berlitz, whose book includes "the world's shortest phrase book in the most (25) languages." Supplemented with gestures, these phrases "can establish an initial communications breakthrough": excuse me, please, thanks, where is, how much is, yes, no and good.

To avoid confusion between languages, he says, "Don't translate the words in your head. Learn to think in the language."

And how does a linguist identify his "native tongue?"

It probably comes down to "What you say," says Berlitz, "when you hit your thumb with a hammer."

For him, it's French.