"Harvard is a very famous American university."
Translation:هارْفارْد جامِعة أَمْريكِيّة مَشْهورة جِدّاً.
Kaet, you are correct, it is a tiny circle, not a dot. It is called a suukun (I am spelling this as it sounds as I am not sure of the correct spelling) and, as you say, it indicates that there is no vowel following that letter.
Vasandl, I agree completely about the font size. I've often wondered if Arabic speakers are required to have excellent vision (or very powerful reading spectacles), because it is only Duo that has small print. Just try to read the Arabic on multi lingual packaging or labels!
However, here is another "fun fact" to look forward to: once you start to read normal documents in Arabic (books, newspapers, letters etc), you don't get the accents (I think they are collectively called tashkeel) at all. You just have to work them out from the context. The one place they are always included is the Holy Quoran.