Dothraki will be full of various affixes. Here are some of the ones that we have seen so far.
First we have an example that was officially mentioned in one of the interviews with David Peterson.
as- -an | positive comparative | asafazhan | hotter |
os- -an | negative comparative | osafazhan | less hot |
as- -an -az | positive superlative | asafazhanaz | hottest |
as- -an -oz | negative superlative | asafazhanoz | least hot |
Other circumfixes we have seen are:
ath- -zar | unknown | athastokhdeveshizaroon | from nonsense |
ath- -ar | derivation? | athjahakar | pride, prowess (formed from the stem jahak meaning hair-braid) |
A couple of the identified suffixes are:
-oon | ablative case | mahrazhoon | from the man, by the man |
-i | plural, diminutive, genetive | lajaki | warriors |
They seem to be both rather common, especially -i. Another suffix is -aan as in arakhaan which is also not known yet. There are also several nouns that end in -asar like for example khalasar, ramasar, fonakasar which suggests that -asar might also be a suffix of some sort.
One thing to keep in mind is that Peterson mentioned in one interview that he has deliberately tried to avoid being straight forward and formulaic when it comes to forming words. He writes:
"For example, in Dothraki, it’s a simple matter to separate affixes from stems, but it’s not always simple to attach a meaning to a given affix. // Looking at the forms above, the stem afazh (“hot”) can be picked out fairly easily, but assigning a single meaning to each affix becomes either a very difficult process, or a trivial process (i.e. simply restating what’s there). However, it would seem a mistake to treat each form as entirely unrelated to the rest (i.e. as if each one had an entirely different affix)"