İ

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 except in Kazakh in which it additionally represents the voiced palatal approximant  and the diphthongs  and. All languages that use it use also its dotless counterpart I but not the basic I|Latin letter I.

In computing
The dotted I is encoded into Unicode with the code point U+0130 (U+0069 for the lowercase letter) as part of the Latin Extended-A block.

Issues
The dotted and dotless I characters have caused issues in computing. Languages like Turkish have four variants of the letter I (opposed to two in English). This causes problems when, instead of the original mapping of i to I, Turkish maps i to the new İ, and ı to I, frequently breaking software logic.

Usage in other languages
Both the dotted and dotless I can be used in transcriptions of Rusyn to allow distinguishing between the letters Ы and И, which would otherwise be both transcribed as "y", despite representing different phonemes. Under such transcription the dotted İ would represent the Cyrillic І, and the dotless I would represent either Ы or И, with the other being represented by "Y".