It seems that all Hebrew words that have a vowel under the letter are pronounced with the letter ("consonant") followed by the vowel. The only exception that I can think of is when a patach is underneath a chet at the end of a word such as in the word נֹח. The word is pronounced noach, not nocha.
The vowel sound is pronounced before the consonant. Why is this an exception?
(This question is applicable to Torah reading, so I'm not intending this as a loose question about the Hebrew language.)
Essentially there should be no vowel, but for certain guttural consonants (specifically, Hei, Chet, and Ayin) it's hard to end a word like that ("NoH"?), so an extra half-vowel is placed before the final consonant. This is not a full Patach, but a half-vowel (not unlike how a Shva Na' isn't counted as a syllable) known as a "furtive Patach" or "פתח גנובה". In classical texts, the Patach is actually written a bit before the letter to indicate this. From Devarim 29:22 in the Aleppo Codex:
