What in the world is a diphthong?!

I like the breakdown at the link in this post. I've also found a simple rule of thumb on where you put the emphasis when you have a word in Spanish you're trying to pronounce:

• When a word has 2 syllables, stress the first syllable.
• When a word has more than 2 syllables, stress the second to the last syllable.
• Clap when you stress the syllable. This is especially helpful for children who don't read yet so they can distinguish audibly. It also adds the kinesthetic learning style.