| Discourse particles are some of the most common spoken "words" in any language and the bane of language purists everywhere. Some common English discourse particles are:
However, every language has it's discourse particles--a quick Google search has come up with the following horribly short list (feel free to /msg me with any others you can think of):
Dutch
- Allee (as in 'Allee, ik ben weg'--'Well, I'm off.')
- Allez
German
Finnish
Icelandic
Danish1
Japanese1
French2
Latin2
Discourse particles serve all sorts of different purposes in spoken language--verbal filler to buy time while you figure out what you wish to say (the most common use by far), transitions from one thought to the next, exaggerations ("He's like, 800 feet tall"), random thinking noises ("Hmm... now where could that cat have gotten off to?"), etc.
Although discourse particles are generally considered Bad Things in the world of public speaking (as umming and ahhing while you're supposed to be addressing a crowd makes you look unprepared, nervous, and not terribly intelligent), they are a normal part of everyday conversation with friends and colleagues. Most of the time you won't even notice them.
1: Thanks to liveforever for the Danish and Japanese particles!
2: Thanks to edamutvivo for the French and Latin particles--keep the additions coming, guys! | 
