why is it that we would say üşÃ¼rsün instead of üşersin??
i mean, we dont say düşÃ¼rsün do we? we say düşersin... help!

I guess we would say üşÃ¼rsün instead of üşersin just because of the vowel harmony. The given above verbs are in the ‘Geniş Zaman’ (Present Simple Tense). The stem of the verm üşÃ¼mek is üşÃ¼-, so we just add the suffix –r- and the personal ending –sün according to the vowel harmony.
As for the second verb... well, it ends with a consonant, that's why we just add -er (there are two suffixes for Geniş Zaman for monosyllabic verbs ending wıth a vowel: -ar and -er). that's it I believe

oh yeahhh... that makes so much sense now.. that actually explains a lot u know hehe.. thanks...

YEAH... thats sth. else which i hate but i think in time, i will pick them up natrually.. i mean, i know the ones which u have said

Yes, dear Salukvadze, it's very complicated. Actually all monosyllabic verbs add -ar or -er, but ther exist 13 verbs that stand out of this rule. They are:
gel-ir
al-ır
bil-ir
var-ır
gör-ür
kal-ır
bul-ur
öl-ür
ver-ir
ol-ur
san-ır
dur-ur.
All the other verbs (i.e. consisting of more than 1 syllable)and ending with the consonant add suffixes again according to the vowel harmony, e.g.
götür-ür
konuş-ur
sevin-ir...

woww... really??? there is only 13 exceptions...?? thanks so much for telling me that.. thats really gonna help me

Oops! Sorry, a misprint. So,
ver-ir
I'll correct the mistake in the previous message