I (letter)

I is the ninth letter of the basic Latin alphabet. It is one of the vowels in many languages. The uppercase form is 'I', while the lowercase form is 'i', commonly written with a dot placed above it.

In Somali written in the Latin script, 'i' is a vowel. Like other vowels in Somali, it can be doubled to indicate length, for example 'ii'. The length of the vowel can change the meaning of a word.

History of the form

The letter's origin can be traced to early Semitic letters, which the Greeks adapted into the letter 'iota'. The Romans took iota and adopted a straight form without a dot. The dot on the lowercase 'i' emerged during medieval handwriting, to distinguish it from adjacent vertical strokes in script.

Relationship with J and Y

For a long period, 'I' and 'J' were the same letter; 'J' later separated into a distinct letter serving as a consonant in many languages. Similarly, in some languages 'i' and 'y' represent the same sound in certain positions.

Use of symbols and units

In mathematics and engineering, 'i' is used to represent the imaginary unit, while 'I' in electrical engineering denotes electrical current. In Roman numerals, 'I' represents one.