The Turkish Alphabet was changed from Ottoman script to a Latin based script soon after the Turkish Republic was declared. Ottoman script was based on the Arabic alphabetic script but this did not adequately cover the phonetics of Turkish.
Kemal Atatürk introduced the new Latin alphabet almost overnight.
The Turkish Alphabet consists of twenty-one consonants and eight vowels.
The alphabet is phonetic as each letter retains its individual pronunciation at all times. There are no diphthongs - except in a few foreign loan words, and no letters "W", "X" or "Q"
Turkish does not as a rule allow two vowels to occur together - there are exceptions of course - but mostly in foreign imported words. Therefore as there are no diphthongs then whenever two vowels occur together, they are each pronounced as a separate sound.
The letter -Y- is considered as a consonant in Turkish, and it is widely used as a buffer consonant to keep vowels apart during word building.
The actual Law No:1353 dated 1st November 1928 which changed the Turkish Alphabet to Roman letters. It became a movement to purify the Turkish language. Despite the fact that only thirty-five to forty percent of Turkish terms were useful in formal language before 1932, this figure is seventy-five to eighty percent today. Those numbers show that attempts to reform and rescue the Turkish language were successful.