Phoenician yodh — "arm, hand", through Greek iota.
I
iota is the narrowest letter in Greek — a single stroke of the pen — and that is why an iota still means the smallest possible amount. The dot is medieval: scribes added it so a single i would not vanish among the strokes of m, n and u in cramped handwriting.
Aguilar · Bailey · Bianchi · Castillo · Collins · Conti · Cunningham · Daniels · Davies · Davis · Diaz · Dixon · Elliott · Ellis
In the modern alphabet this letter is number 9 of 26. Before it comes H, after it J. The order itself is inherited: Latin took it from Greek, Greek from Phoenician, and the sequence has survived largely unchanged for about three thousand years. Every rearrangement since has been an insertion, not a reshuffle.
This is a vowel: the syllable rests on it, and vowels set the rhythm of a name. In a corpus of 315 surnames none begins with it; 5 end on it. Among the 96 given names in the base it appears in 36. The surname carrying the most of it is Bianchi, with 2.
Michael · William · David · Richard · Christopher · Daniel · Timothy · Nicholas · Eric · Benjamin · Patrick · Liam
These letters came from the Greek alphabet.