Turkmen (Latin)
4.000.000 speakers
18 language specific characters
ISO 639 code: tuk
Turkmen is a Turkic language spoken by about 4 million people in Turkmenistan, Afghanistan, Germany, Iran, Iraq, Kazakhstan, Kyrgyzstan, Pakistan, Russia (Asia), Tajikistan, Turkey (Asia), USA and Uzbekistan.
Turkmen only started to appear in writing at the beginning of the 20th century, when it was written with the Arabic script. Between 1928 and 1940 it was written with the Latin alphabet, and from 1940 it was written with the Cyrillic alphabet. Since Turkmenistan declared independence in 1991, Turkmen has been written with a version of the Latin alphabet based on Turkish.
source
wikipedia.org, omniglot.com & ethnologue.com
younger brothers