When the Ancient Greeks adopted the alphabet, they had no use for the glottal stop that the letter had denoted in Phoenician and other Semitic languages, so they used the sign to represent the vowel /a/, and kept its name with a minor change (alpha). In the earliest Greek inscriptions after the Greek Dark Ages, dating to the 8th century BC, the letter rests upon its side, but in the Greek alphabet of later times it generally resembles the modern capital letter, although many local varieties can be distinguished by the shortening of one leg, or by the angle at which the cross line is set.
The Etruscans brought the Greek alphabet to their civilization in the Italian Peninsula and left the letter unchanged. The Romans later adopted the Etruscan alphabet to write the Latin language, and the resulting letter was preserved in the modern Latin alphabet used to write many languages, including English.
The letter has two minuscule (lower-case) forms. The form used in most current handwriting consists of a circle and vertical stoke ("ɑ"), called Latin alpha or "script a". Most printed material uses a form consisting of a small loop with an arc over it ("a"). Both derive from the majuscule (capital) form. In Greek handwriting, it was common to join the left leg and horizontal stroke into a single loop, as demonstrated by the Uncial version shown. Many fonts then made the right leg vertical. In some of these, the serif that began the right leg stroke developed into an arc, resulting in the printed form, while in others it was dropped, resulting in the modern handwritten form.
In English, "a" by itself frequently denotes the near-open front unrounded vowel (/æ/) as in pad, the open back unrounded vowel (/ɑː/) as in father, or, in concert with a later orthographic vowel, the diphthong /eɪ/ as in ace and major, due to effects of the great vowel shift.
In most other languages that use the Latin alphabet, "a" denotes an open front unrounded vowel (/a/). In the International Phonetic Alphabet, variants of "a" denote various vowels. In X-SAMPA, capital "A" denotes the open back unrounded vowel and lowercase "a" denotes the open front unrounded vowel.
"A" is the third common used letter in English, and the second most common in Spanish and French. In one study, on average, about 3.68% of letters used in English tend to be ‹a›s, while the number is 6.22% in Spanish and 3.95% in French.
"A" is often used to denote something or someone of a better or more prestigious quality or status: A-, A or A+, the best grade that can be assigned by teachers for students' schoolwork; A grade for clean restaurants; A-List celebrities, etc. Such associations can have a motivating effect as exposure to the letter A has been found to improve performance, when compared with other letters.