What is Esperanto like?

Esperanto is largely based on Latin, but also borrows from modern European languages like French, English and Polish. Zamenhof chose word roots that would be recognizable to the greatest number of people. In this way, anyone who speaks a European language already has a large amount of vocabulary in Esperanto. The pronunciation is easy, similar to Italian with some influence from Eastern European languages.
Because of the 'internationality' of the vocabulary, and the relative simplicity of the grammar, Esperanto is very easy to learn. Estimates range from 4 times easier to learn than national languages, to as much as 10 times easier to learn Esperanto!
Zamenhof knew that Esperanto needed to be simple. So he devised Esperanto to have only 16 basic rules of grammar or syntax with no exceptions, unlike French or English or other national languages which seem to have endless exceptions. He also knew that it needed to be easy to read and write. He created a simple orthography with a basic rule of 1-sound 1-symbol. An 'e' will always be pronounced the same way, a 'c' is always pronounced the same way etc., and every letter is pronounced - no silent letters.
This is a far cry from English. Look at the following words:
throughthoroughthoughttough
The 'ou' combination is pronounced four different ways and the 'gh' combination is either silent or makes an 'f' sound. That's the orthographic nightmare of modern English. French isn't much better. This doesn't happen in Esperanto. Zamenhof also chose sounds that were common to the most languages. At most you'll find one or two sounds that you aren't familiar with in your native language, and these will probably be easy to learn. The stress is always on the second to last syllable. All this makes Esperanto easy to pronounce. You can read and pronounce correctly even words you've never seen or heard before, once you learn the alphabet, which takes only a few minutes.