16 - āyin
Similar to א, the consonant ע is a stop of the air flow that precedes a vowel. Technically speaking, א is a glottal stop whereas ע is a pharyngeal stop. However, over time, the difference between the two has become much less pronounced. In spoken Hebrew ע is often silent; yet in writing, it introduces syllables that begin with a vowel sound.
עברית (Hebrew)
נעים (pleasant)
When ע is the last letter of a word, it is pronounced /a'/ when preceded by /e/, /i/, /o/, or /u/ (any vowel but /a/):
שבוע (week)