Do you think that a goldfish knows what water is? No, he is unaware of it because it has been his unceasing environment for his whole life. Since he has no concept or experience of “non-water,” he does not consider “water” to be much of a factor in his existence. He does not even know that he’s wet.
Primitive man probably took air for granted in the same way. He was probably as ignorant as a goldfish about the most essential feature of his surroundings.
In the same line of thinking, some inhabitants of the planet are unaware that when they speak, they speak a language. If you have never heard someone speaking in an incomprehensible way, you might think that speech is as automatic and natural as being in the air (if you are a person) or in the water (if you are a goldfish). In modern times, this would be literally true in only the most primitive and isolated of societies. It is widely true, in a way, in the United States whenever a person is so densely surrounded by English speakers that he or she easily lapses into the supposition that everybody else speaks and thinks in the same way.
I have known a couple of persons who were convinced that a foreigner could understand English if only you said everything either v-e-r-y s-l-o-w-l-y or VERY LOUDLY, as if speaking a foreign language was a symptom of a hearing problem.
In truth, the language you speak has a strong influence on how you perceive the world. The interplay between reality, language and thought is a subject to which philosophers and academics have devoted much energy and have stirred up much controversy. (To start with this subject, take a look at a collection of essays written by Benjamin Lee Whorf called Language, Thought and Reality (originally published in 1939, reprinted by MIT Press, 1964).) You and I do not have to contribute to the conceptual debates: but we should be able to agree that the language you speak does have some influence — maybe a lot of influence — on how you see the world. So, the study of another language not only helps you to understand how others see their world, but more importantly, it helps you realize how much your own language determines how you see your world.
In short, to understand your native tongue better, take a detailed look at the native tongue of someone else. Does it matter which one? Probably not: choose one that has to do with your ethnic heritage or culture; or you might start out with the “easier” ones — the ones most similar to English. Because about 40% of English word origins come from Norman French, and an equal proportion from Saxon, you will discover lots of cognates and correlative phrases in modern French and German. Twenty percent or so of modern English is derived from Latin as it was written in the Middle Ages. Latin would also be a good choice, as it can also be useful in more ways than simply explaining word origins. Dutch and Scandinavian tongues are also similar to English in many respects.
Languages with other alphabets — like Hebrew, Arabic, Russian and Greek — pose additional challenges, but also can be rewarding subjects of study. Other possibilities include languages outside the Indo-European and Semitic families: Native American, Asian and African languages. You could even decide to learn ASL (American Sign Language).
The point of all this for purposes of mastering your native tongue is that you will inevitably have lots of “aha!” moments with respect to American English. Foreign language study heightens your awareness of language in general. Fortunately, you reap this benefit, even if you do not attain mastery of the language studied.
Here are a couple of examples of how the study of a language other than English can broaden your understanding of things in general. They make you aware that there are things and ideas in the world that can not be expressed precisely in the English language.
Let’s imagine that you have a son or daughter who gets married. That makes you a mother-in-law or father-in-law to someone. Now that someone has a mother and father (let’s assume). They, like you, have an important interest in the married couple, and they, like you, will want to help the newlyweds navigate the sometimes puzzling paths of matrimony. You will get to know them. Now . . .
What is the name in English for the relationship between you and the parents of your child’s spouse?
Give up? There is none. We say, rather lamely, I think: “The parents of my son-in-law” (or “daughter-in-law”). That’s a description, not the name of a relationship.
Spanish has a precise word for this relationship: consuegro (or consuegra, if it’s about a female). The “suegro(a)” part means parent-in-law. Even more interestingly, the “con-” part means “with,” suggesting that the two sets of parents of the newlyweds are in a sort of joint venture, being suegros with each other, a relationship defined by their joint focus on the well-being of the happy couple.

Has Spanish been able to teach you something about relationships that English could not? How about this one: What is the name in English of the relationship between the father of a child and the child’s godfather? The two men are indeed connected by their mutual interest in the child — one by blood and the other by promise and commitment. English does not articulate this relationship either. Perhaps it is not important enough to English-speakers to merit a term of its own. In Spanish, it’s “compadre,” made up of “padre” (father) and “com-” (with). The feminine form is comadre. Like “consuegro,” compadre uses the “with” particle to emphasize that the two men in the example have a relationship with each other by virtue of their respective duties to the child. Of course, nowadays, “compadre” is used in Mexico the way “buddy” is used in the U.S. It is only natural that the word evolved into meaning “close friend.”
Here are two more examples, both from German: Schadenfreude and Gemütlichkeit. In both cases, we can describe what these words are getting at, but we can’t name a word in English that means the same thing. Moreover, and this is the main point of the words as illustrations, it is even difficult to capture their meaning, even in a couple of sentences in English:
Schadenfreude is the sense of well-being that one gets from another person’s harm or misfortune (schaden=to harm; Freude=joy). Close approximations are “malicious joy,” “gloating,” and “spitefulness.” Each of these terms misses the mark: there is nothing necessarily malicious about Schadenfreude, as it is an internal, emotional-psychological state, with no malice necessarily implied. Often it connotes the satisfaction felt when someone “got what was coming to him,” as when someone blows past you on the highway at 90 miles an hour, only to be pulled over by a state trooper. More recently the term has been extended to embrace pleasure in another person’s undeserved misfortune, which seems to me to be a little sick.

The second term, Gemütlichkeit, is said to include the quality of being snug, cozy and inviting (in the case of a location), and (in the case of human behavior) friendly, pleasing and sociable, all conspiring to create in one a cheerful mood, a sense of unhurried relaxation and of belonging. “Pleasant” is a very loose approximation, but completely lackluster. It does not even come close to expressing the intensity, the positive feeling, the joie de vivre of Gemütlichkeit.
These examples are merely words that describe concepts that English does not capture. Foreign language also peels back other layers of meaning, dealing with expressions and idioms.
For example, in Brazilian Portuguese, it is common to use (or hear) the expression, “Para o inglés ver.” Literally, it means “For the Englishman to see.” It really means to do something just for the sake of show, or to arrange a false front, or to set up something merely for its surface appearance. In Brazil’s colonial times, during the age of exploration, Portugal was in competition with Spain, as was England. Portugal and England were allies against Spain, especially in the New World. As a result, the English were welcomed into Brazil as investors and builders of infrastructure, like harbors and railways. And, like all investors, the English sent in auditors to make sure their money and plans were being carried out to the letter. Naturally, when the auditors arrived, the locals would do everything possible to give them a favorable impression, even if it meant “fixing” the books and engaging in a little theater. Centuries later, the expression is still commonly used, perhaps by many persons who have no idea of its historical origin.

Another example of an idiom is the German expression, “Unter vier Augen.” It means, literally, “Under four eyes.” The phrase is used to express confidentiality or privacy. To say or do something “unter vier Augen” is to share it with just one other person, and with the mutual commitment that no one else will know about it. An element of trust is implicit. (After all, “confide” means “to have faith with” [another].) The mention of the eyes should be notable to us English-speakers. We focus our attention on the eyes of another person because they are windows into his or her feelings, mind or soul. The use of “four” is also striking. It expresses a common bond and commitment between the two persons. Equivalent expressions in English focus only on the other person, without including the speaker: “Don’t tell a soul” and “Promise you won’t tell”. This may give us a small insight into German culture, but it also tells us something that we may not have noticed about English.