In Ibero-Romance languages, the "í" is not considered a letter, but the letter "i" with an accent. It is used to denote an "i" syllable with abnormal stress.
Italian
Í/í is a variant of I carrying an acute accent; it represents an /i/ carrying the tonic accent. It is used only if it is the last letter of the word except in dictionaries or when a different pronunciation may affect the meaning of a word: víola ("violates", pronounced[ˈviːola]) and viòla ("violet", pronounced['vjɔːla]).
Karakalpak
Í is the 13th letter of the Karakalpak alphabet. It represents /ɯ/. Its preferred lowercase form is ⟨ı⟩.