The Ethnologue: facts about the world's languages.
Sounds of the World's Animals: how to say "woof woof" in 36 languages.
The International Phonetic Alphabet.
Ask a Linguist: a place where anybody can get any linguistic question answered by a linguist
Sammy, the Interactive Sagittal Section.
More animated sagittal sections, for the sounds of English and Spanish.
A video of the tongue's position while producing some vowels.
Some vowels to listen to.
A website where you can hear all the sounds in the IPA.
A demonstration of differences in aspiration.
Some more exotic sounds.
Beyond pulmonic egressive: clicks, implosives, ejectives.
More on spectrograms.
The McGurk Effect.
A new theory about the languages of Europe; they were constructed out of Basque roots by Benedictine monks.
One reason why megalocomparison is a bad idea.