Over the course of human history, thousands of languages have developed from what was once a much smaller number. How did we end up with so many? And how do we keep track of them all? Alex Gendler explains how linguists group languages into language families, demonstrating how these linguistic trees give us crucial insights into the past.

Taylor Swift's song "Wildest Dreams" was the fifth chart-topper from her album 1989. The music video, directed by Joseph Kahn, references classic Hollywood romances.

Learn about the states of matter, solids, liquids and gases, how they're different and where they're found in everyday life.

This performance of "Wonderful Tonight," one of Eric Clapton's later hits, features dynamic solos by Clapton and singer Katie Kissoon. Enjoy!

We all know that whales are endangered due to hunting and pollution, but do you know how important they are for the ocean and the environment? This video shows how essential a healthy population of whales is to the ocean ecosystem. Creative Commons Attribution license (reuse allowed). Video was not modified. Please visit sustainablehuman.org for credits and more information.

Sigrid talks about some of the ways she learned how to speak Italian and French.

Minidisco presents a song that reviews the names of the family members as well as the names of the different fingers! Enjoy!

David and Ben Crystal explain what goes into original pronunciation (OP) productions of Shakespeare and what they reveal about the history of the English language.

American singer Christina Perri sings her hit "Jar of Hearts," a song about heartbreak. She is a rising star in the United States and ready to take on the world at large.

Taylor Swift discusses her song "Out of the Woods" and why it is representative of the goal she had for her album 1989.

With the Rainforest Alliance certification, everyday purchases can help prevent deforestation and climate change, protect wildlife, alleviate poverty and transform business practices. Choose products with the seal of the green frog when purchasing coffee, cocoa, tea, flowers, fruit, paper, and wood products.

Steve Skaith of the English band Latin Quarter plays "The Spearcarrier." A "spear carrier" is a nickname for a character in a movie or play who appears only in the background, generally in a non-speaking role.

Taylor Swift reflects back on the tour for her album 1989, which was attended by over two million fans. Featuring behind the scenes footage and performances of the song "New Romantics."

Have you ever wondered why English seems to have roots in so many different languages? Here is a look at what words the Anglo-Saxons and Vikings brought to the English language.

Penny invents a quiz to find out whether Sheldon or Leonard is smarter, which only reveals that both of them are completely uninformed about popular culture with the exception of Star Trek.

Justin James began writing songs when he was 20 years old and now tours the world performing his music. Releases include Islands (2013), A Beautiful Life (2011), Perfect Sometimes (2009), and Sun Drenched (2007). In this video, you can hear many samples of his songs in performances and music videos.

Justin James is a singer from Vancouver, British Columbia. This song is from his record Islands.

Here is a short animated video about the importance of fisheries for food security, health and growth in developing countries, highlighting the commitment of the EU to helping promote sustainable management of seafood resources and inclusive opportunities for trade and growth.

James Bay is an English singer-songwriter and guitarist. His single "Hold Back the River" is certified platinum and appears on his debut album "Chaos and the Calm."

Bryan Adams and The Who perform Behind Blue Eyes, one of The Who's most well-known songs, at The Royal Albert Hall, London, in aid of the Teenage Cancer Trust.

The cover letter is an essential document when submitting a job application. Here you can learn about what function a cover letter should serve.

Sigrid describes her time in Basel, and how she ended up visiting France and Italy as well.

This dazzling short film references the Rosetta mission of the European Space Agency, which intends unlock the mysteries of the comets and, in doing so, the origins of our Solar System.

Enjoy this excerpt of Led Zeppelin performing "Stairway to Heaven" at Earls Court. Written by guitarist Jimmy Page and vocalist Robert Plant, the song is widely acknowledged as one of the greatest rock songs of all time.