Martin Haspelmath has posted a fascinating set of slides (PDF, in German) about languages. Some facts:

• About 7000 languages are spoken; more than 800 in Papua New Guinea; 170 in the US; 7 in Germany.
• About 150 languages are spoken in Europe.
• 280 languages are spoken by more than one million people each, 450 languages by less than one hundred people each.
• The ranking of languages: 1. Mandarin. 2. English. 3. Spanish. 4. Hindi. 5. Arabic. 6. Portuguese. 7. Bengali. 8. Russian. 9. Japanese. 10. German.
• Roughly half of the world population speak one of these ten languages.
• The Georgian language allows for up to 7 consonants in a row.
• All languages feature words and sentences; questions and negation; names; expressions for “up” and “down.”
• Not all languages distinguish tempi or feature adjectives or expressions for numbers or for “and, or, left, right.”