Quick answer
И и is the ee of “see”. It softens the consonant in front of it: ти́хо begins like “tyee”, not “tee”.
Ии
Ии
i
и́мяname
How to say it
The ee of “see”, short and bright. Unstressed it stays recognisable, unlike о and а.
и́мяname
кни́гаbook
ти́хоquietly
си́нийblue
мирpeace, world
иand
И, Ы and Й
И is bright and front. Ы is the same length but pulled far back — compare би́ть and быть. Й is not a vowel at all, but the y of “boy”. Three letters, three different jobs, one family resemblance.
И as a whole word
On its own, и means “and”. One letter, one word, and extremely common: ты и я. After ж, ш, ч, щ the spelling rule forces и even where the sound is closer to ы: жить, маши́на.
Typical mistakes
Reading и as an n
И is a vowel: “ee”
It looks like a mirrored N.
Pronouncing ти́хо as “tee-kho”
“tyíkho”
И softens the consonant before it.
Check yourself
Which word contains И?
и́мя — name.