Learn Turkish: Uyumadan önce ruhumu hissediyorum. - I feel my soul before sleeping.

This uses the lesson's pattern: verb root + -mAdAn önce. We take the verb root uyu- (to sleep), add -madan, and follow it with önce (before). While -madan usually means 'without' on its own, when paired with önce it becomes the standard Turkish way to say 'before doing [verb]'.

Why does the word ruh (soul) have two U's at the end to make ruhumu?

Let's break down the suffixes! First, we add the possessive suffix -um to make ruhum (my soul). Then, because 'my soul' is the specific direct object you are feeling, it needs the accusative case suffix. According to vowel harmony, that's an -u. So, ruh + -um + -u becomes ruhumu.

The dictionary form for 'to feel' is hissetmek. Why does it change to hissediyorum here?

Hissetmek is a compound verb made from his (feeling) and the helper verb etmek (to do). Two things happen here! First, when the Arabic loanword his joins with etmek, the s doubles. Second, when the continuous suffix -iyor is added, the t at the end of et- softens into a d. This is a common consonant mutation, turning hisset- into hissed-.