The "o" in Monitoring is a closed vowel, (meaning that there is a consonant immediately following the vowel,) therefore creating a short vowel sound. So the "o" would make a short o sound "ahh".
Then, due to use of several vowels in the word, you'll find that "monitoring" contains a schwa, which is referred to as a lazy or unstressed vowel sound. Most multi-syllabic words have a schwa sound: Ex --telephone (the 2nd e sounding like "uh") Elephant., Enemy (e sounding like "uh")
The reason for that is so the words can be said quickly and easily. If you tried saying elephant or telephone and stressed every vowel, it would be quite difficult.
Most schwa's make an "uh" or "ih" sound.
