I have been smoking since I was nineteen. - On dokuz yaşımdan beri sigara içiyorum.
The captain went to sea when he was nineteen. - Kaptan on dokuz yaşındayken denize gitti.
The cardinal number occurring after eighteen and before twenty, represented in Roman numerals as XIX and in Arabic numerals as 19. It is the last/largest of the "teens"
[ 'on, 'än ] (preposition.) before 12th century. Middle English an, on, preposition & adverb, from Old English; akin to Old High German ana on, Greek ana up, on.