• With over 100 million native speakers of German. It is the most commonly spoken native language in Europe.
• More than 750 American companies manufacture, market, and do research in Germany. Because Germany is the leading exporter and the third largest economy in the world.
• There are 128 German companies employing over 35,000 people in Ohio alone. German corporations have invested more than $ 35 billion in the United States, employing more than 700,000 Americans.
• .DE is the second most popular domain name on the Internet.
• A knowledge of German language and culture significantly improves job opportunities.
• German language publications amount to some 80,000 books a year, or 10% of the world output. But only about 5% of them are translated into English.
• German translators are needed.
• German is not difficult to learn. It is historically related to English and shares many words and structures with English.
• Scholarships and awards are awarded to German students at every level including the intro levels.
• With two years of university German you can begin to function, reading, writing, speaking, and understanding spoken German.

With thanks from J. Dorsay, who recommended a page "Learn German Fast" from the website Studying in Germany, here are more reasons why you should learn German!

• Germany is the world’s second-largest exporter.
• The German economy ranks number one in Europe and number four worldwide. Its economy is comparable to that of all the world’s Spanish-speaking countries combined.
• Germany is home to numerous international corporations.
• Direct investment by Germany in the United States is over ten billion dollars. 
• German has the largest number of native speakers in the European Union (far more than English, Spanish, or French).
• German is among the ten most commonly spoken languages in the world. It is also a lingua franca of Central and Eastern Europe. And as for “all Germans speak English anyway”? That’s pure myth.
• 22 Nobel Prizes in Physics, 30 in Chemistry, and 25 in Medicine have gone to scientists from the three major German-speaking countries, while many laureates from other countries received their training in German universities. Eleven Nobel Prizes in Literature have been awarded to German-language writers, and seven Germans and Austrians have received the Peace Prize.
• Germans are world leaders in engineering.
• German and English are similar. Many words in German sound and/or look the same as equivalent English words, because the two languages share the same “grandparent.”
• The German-speaking world has produced some of the most revered filmmakers of the 20th century – from Fritz Lang to Rainer Werner Fassbinder, Wim Wenders and a new generation of transnational directors such as Tom Tykwer and Fatih Akin. German and Austrian filmmakers such as Lang, Billy Wilder and Ernst Lubitsch also shaped the history of Hollywood.
• German is the language of Goethe, Marx, Nietzsche, and Kafka, of Mann, Brecht, and Grass. Mozart, Bach, Beethoven, and Schubert, Brahms, Schumann, Wagner, Mahler, and Schoenberg spoke and wrote German, as did Freud, Weber, Einstein, and Heisenberg, Kant, Hegel, and Heidegger.
• German is the second most commonly used scientific language in the world.
• 18% of the world’s books are published in German, and relatively few of these ever appear in English translation.
• German is the gateway to a world-class higher education.
• Many of the Western world’s most important works of philosophy, literature, music, art history, theology, psychology, chemistry, physics, engineering and medicine are written in German and continue to be produced in German.