A

Different glyphs of the lowercase letter A.

During Roman times, there were many variant forms of the letter "A". First was the monumental or lapidary style, which was used when inscribing on stone or other "permanent" media. There was also a cursive style used for everyday or utilitarian writing, which was done on more perishable surfaces. Due to the "perishable" nature of these surfaces, there are not as many examples of this style as there are of the monumental, but there are still many surviving examples of different types of cursive, such as majuscule cursive, minuscule cursive, and semicursive minuscule. Variants also existed that were intermediate between the monumental and cursive styles. The known variants include the early semi-uncial, the uncial, and the later semi-uncial.[6]

Typographic variants include a double-storey a and single-storey ɑ.

Blackletter A	Uncial A	Another Blackletter A
Modern Roman A	Modern Italic A	Modern script A

At the end of the Roman Empire (5th century AD), several variants of the cursive minuscule developed through Western Europe. Among these were the semicursive minuscule of Italy, the Merovingian script in France, the Visigothic script in Spain, and the Insular or Anglo-Irish semi-uncial or Anglo-Saxon majuscule of Great Britain. By the ninth century, the Caroline script, which was very similar to the present-day form, was the principal form used in book-making, before the advent of the printing press. This form was derived through a combining of prior forms.[6]

Road sign in Ireland, showing the Irish "Latin alpha" form of "a" in lower and upper case forms.

15th-century Italy saw the formation of the two main variants that are known today. These variants, the Italic and Roman forms, were derived from the Caroline Script version. The Italic form, also called script a, is used in most current handwriting; it consists of a circle and vertical stroke on the right ("ɑ"). This slowly developed from the fifth-century form resembling the Greek letter tau in the hands of medieval Irish and English writers.[4] The Roman form is used in most printed material; it consists of a small loop with an arc over it ("a").[6] 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. Graphic designers refer to the Italic and Roman forms as "single decker a" and "double decker a" respectively.

Italic type is commonly used to mark emphasis or more generally to distinguish one part of a text from the rest (set in Roman type). There are some other cases aside from italic type where script a ("ɑ"), also called Latin alpha, is used in contrast with Latin "a" (such as in the International Phonetic Alphabet).

In modern English orthography, the letter ⟨a⟩ represents at least seven different vowel sounds:

• the near-open front unrounded vowel /æ/ as in pad;
• the open back unrounded vowel /ɑː/ as in father, which is closer to its original Latin and Greek sound;[5]
• the diphthong /eɪ/ as in ace and major (usually when ⟨a⟩ is followed by one, or occasionally two, consonants and then another vowel letter) – this results from Middle English lengthening followed by the Great Vowel Shift;
• the modified form of the above sound that occurs before ⟨r⟩, as in square and Mary;
• the rounded vowel of water;
• the shorter rounded vowel (not present in General American) in was and what;[4]
• a schwa, in many unstressed syllables, as in about, comma, solar.

The double ⟨aa⟩ sequence does not occur in native English words, but is found in some words derived from foreign languages such as Aaron and aardvark.[7] However, ⟨a⟩ occurs in many common digraphs, all with their own sound or sounds, particularly ⟨ai⟩, ⟨au⟩, ⟨aw⟩, ⟨ay⟩, ⟨ea⟩ and ⟨oa⟩.

⟨a⟩ is the third-most-commonly used letter in English (after ⟨e⟩ and ⟨t⟩) and French, the second most common in Spanish, and the most common in Portuguese. About 8.167% of letters used in English texts tend to be ⟨a⟩;[8] the number is around 7.636% in French,[9] 11.525% in Spanish,[10] and 14.634% for Portuguese.[11]

In most languages that use the Latin alphabet, ⟨a⟩ denotes an open unrounded vowel, such as /a/, /ä/, or /ɑ/. An exception is Saanich, in which ⟨a⟩ (and the glyph Á) stands for a close-mid front unrounded vowel /e/.

In phonetic and phonemic notation:

• in the International Phonetic Alphabet, ⟨a⟩ is used for the open front unrounded vowel, ⟨ä⟩ is used for the open central unrounded vowel, and ⟨ɑ⟩ is used for the open back unrounded vowel.
• in X-SAMPA, ⟨a⟩ is used for the open front unrounded vowel and ⟨A⟩ is used for the open back unrounded vowel.

• Æ æ : Latin AE ligature
• A with diacritics: Å å Ǻ ǻ Ḁ ḁ ẚ Ă ă Ặ ặ Ắ ắ Ằ ằ Ẳ ẳ Ẵ ẵ Ȃ ȃ Â â Ậ ậ Ấ ấ Ầ ầ Ẫ ẫ Ẩ ẩ Ả ả Ǎ ǎ Ⱥ ⱥ Ȧ ȧ Ǡ ǡ Ạ ạ Ä ä Ǟ ǟ À à Ȁ ȁ Á á Ā ā Ā̀ ā̀ Ã ã Ą ą Ą́ ą́ Ą̃ ą̃ A̲ a̲ ᶏ[15]
• Phonetic alphabet symbols related to A (the International Phonetic Alphabet only uses lowercase, but uppercase forms are used in some other writing systems):
  • Ɑ ɑ : Latin letter alpha / script A, which represents an open back unrounded vowel in the IPA
  • ᶐ : Latin small letter alpha with retroflex hook[15]
  • Ɐ ɐ : Turned A, which represents a near-open central vowel in the IPA
  • Λ ʌ : Turned V (also called a wedge, a caret, or a hat), which represents an open-mid back unrounded vowel in the IPA
  • Ɒ ɒ : Turned alpha / script A, which represents an open back rounded vowel in the IPA
  • ᶛ : Modifier letter small turned alpha[15]
  • ᴀ : Small capital A, an obsolete or non-standard symbol in the International Phonetic Alphabet used to represent various sounds (mainly open vowels)
  • ^{A a} ᵄ : Modifier letters are used in the Uralic Phonetic Alphabet (UPA)[16] (sometimes encoded with Unicode subscripts and superscripts)
  • _a : Subscript small a is used in Indo-European studies[17]
  • ꬱ : Small letter a reversed-schwa is used in the Teuthonista phonetic transcription system[18]
  • Ꞻ ꞻ : Glottal A, used in the transliteration of Ugaritic[19]

• ª : an ordinal indicator
• Å : Ångström sign
• ∀ : a turned capital letter A, used in predicate logic to specify universal quantification ("for all")
• @ : At sign
• ₳ : Argentine austral
• Ⓐ : anarchy symbol

• 𐤀 : Semitic letter Aleph, from which the following symbols originally derive[20]
  • Α α : Greek letter Alpha, from which the following letters derive[21]
    • А а : Cyrillic letter A[22]
    • Ⲁ ⲁ : Coptic letter Alpha[23]
    • 𐌀 : Old Italic A, which is the ancestor of modern Latin A[24][25]
      • ᚨ : Runic letter ansuz, which probably derives from old Italic A[26]
    • 𐌰 : Gothic letter aza/asks[27]
• Ա ա : Armenian letter Ayb