I, or ı, called dotless i, is a letter used in the Latin-script alphabets of Azerbaijani, Crimean Tatar, Gagauz, Kazakh, Tatar and Turkish. It commonly represents the close back unrounded vowel /ɯ/, except in Kazakh where it represents the near-close front unrounded vowel /ɪ/. All of the languages it is used in also use its dotted counterpart İ while not using the basic Latin letter I.
In scholarly writing on Turkic languages, ï is sometimes used for /ɯ/.
Ğ (g with breve; minuscule: ğ) is a Latin letter found in the Turkish and Azerbaijani alphabets as well as the Latin alphabets of Zazaki, Laz, Crimean Tatar, Tatar, and Kazakh. It traditionally represented the voiced velar fricative /ɣ/ or the voiced uvular fricative /ʁ/. However, in Turkish, the phoneme has in most cases been reduced to a silent letter, serving as a vowel-lengthener. But for Crimean Tatar spelling in Romania it represents the voiced palato-alveolar affricate /d͡ʒ/.
İ, or i, called dotted I or i-dot, is a letter used in the Latin-script alphabets of Azerbaijani, Crimean Tatar, Gagauz, Kazakh, Tatar, and Turkish. It commonly represents the close front unrounded vowel /i/ except in Kazakh in which it additionally represents the voiced palatal approximant /j/ and the diphthongs /ɪj/ and /əj/. All languages that use it also use its dotless counterpart I, but not the basic Latin letter I.
S-cedilla (majuscule: Ş, minuscule: ş) is a letter used in some of the Turkic languages. It occurs in the Azerbaijani, Gagauz, Turkish, and Turkmen alphabets. It is also planned to be in the Latin-based Kazakh alphabet.It is used in Brahui, Chechen, Crimean Tatar, Kurdish, and Tatar as well, when they are written in the Latin alphabet.
It commonly represents /ʃ/, the voiceless postalveolar fricative (like sh in shoe).
Ü (lowercase ü) is a Latin script character composed of the letter U and the diaeresis diacritical mark. In some alphabets such as those of a number of Romance languages or Guarani it denotes an instance of regular U to be construed in isolation from adjacent characters with which it would usually form a larger unit; other alphabets like the Azerbaijani, Estonian, German, Hungarian and Turkish ones treat it as a letter in its own right. In those cases it typically represents a close front rounded vowel [y] .
Although not a part of their alphabet, Ü also appears in languages such as Finnish and Swedish when retained in foreign proper names like München ("Munich"). A small number of Dutch and Afrikaans words employ the character to mark vowel hiatus (e.g. reünie /reːyˈni/ ("reunion"), a loanword marked with diaeresis to suppress the native reading of eu as a digraph pronounced /øː/).