і / и

In the Cyrillic script used for Ukrainian, these two vowels represent different phonemes.

1. The Letter і (Close Front Unrounded Vowel /i/):
This letter sounds like the 'ee' in 'meet'. Its most important job is to soften (palatalize) the consonant that comes before it. For example, in the word дім (house), the 'd' is soft.

• Used in plural adjective endings (нові, сині).
• Used in soft-stem masculine adjectives (синій).
• One of the words for 'and', though it alternates with 'й' and 'та' to maintain the Law of Euphony.
• Frequently appears in closed syllables (ending in a consonant) and undergoes alternation with 'о' or 'е' when the word changes form and the syllable becomes open (e.g., кіт -> кота, стіл -> стола).

2. The Letter и (Retracted Close-Mid Front Vowel /ɪ/):
This letter sounds like the 'i' in 'bit' or 'hit'. It is a hard vowel, meaning the consonant before it stays non-palatalized. In the word дим (smoke), the 'd' is hard.

• Used in masculine hard-stem adjectives (новий).
• While 'і' is the standard for starting words, 'и' is used at the beginning of a few native words (ирій, икати), interjections (ич!), and certain foreign names (Кім Чен Ин).

3. The 'Rule of Nine' for Loanwords:
In common international words (like система or директор), we use и after nine specific consonants: д, т, з, с, ц, ч, ш, ж, р, but only when followed by another consonant (except 'й'). If one of these nine consonants is followed by a vowel or 'й', we must use і instead (e.g., радіо, діаграма, позиція). In other positions, і is typically used (e.g., кіно). If the /i/ sound follows another vowel in a loanword, the letter ї is used (e.g., мозаїка, наївний). Note that this rule applies primarily to common nouns. For proper names, foreign surnames use і after д, т, з, с, р (e.g., Дікенс), but require и after the hushing consonants and ц (ж, ч, ш, щ, ц) (e.g., Вашингтон, Шиллер). Geographic names follow the Rule of Nine for hushing consonants and ц (taking и), but have specific divergence rules for the other consonants (д, т, з, с, р), where they usually take і unless they are traditional exceptions or end in -ика/-ида (e.g., Міссісіпі, but Америка). Additionally, some older, fully assimilated loanwords take и after consonants not included in the 'Nine' and simply need to be memorized (e.g., лимон, вимпел, імбир, кипарис, спирт), alongside a handful of established religious loanwords (e.g., єпископ, митрополит, християнство).