The letter B probably started as a pictogram of the floorplan of a house in Egyptian hieroglyphs or the Proto-semitic alphabet.

By 1500 BC, the Phoenician alphabet's letter had a linear form that served as the basis for all later forms, which appeared in both the angular and more rounded forms. Its name must have corresponded closely to the Hebrew beth.

When the Ancient Greeks adopted the alphabet, they changed its name to beta and turned the letter upside-down and later added a second loop. In earlier Greek inscriptions, the letter faces to the left, but in the Greek alphabet of later times it faces to the right, although there continued to be variations between pointed and rounded loops.

The Etruscans brought the Greek alphabet to what is now Italy and left the letter unchanged. The Romans later adopted the Etruscan alphabet to write Latin, and the resulting letter, with rounded loops, has been preserved in the modern Latin alphabet used to write many languages, including English.

The Semitic letter Dâlet probably developed from the logogram for a fish or a door. In Semitic, Ancient Greek (Modern Greek /ð/) and Latin the letter was pronounced /d/, in the Etruscan alphabet the letter was superfluous but still maintained (see letter B). Greek letter: Δ (capital) or δ (small) (Delta).

J was originally a capital of I.

Petrus Ramus (d. 1572) was the first to make a distinction between I and J. Originally, both I and J were pronounced (see IPA) as [i], [i:], and [j]; but Romance languages developed new sounds (from former [j] and [g]) that came to be represented as I and J; therefore, English J (from French J) has a sound quite different from I.

In other Germanic languages J stands for [j]. This is also true of Slavic languages that use the Latin alphabet as well as in Hungarian, Albanian, and Finnish, where it can never be a fricative.

In modern standard Italian only foreign or Latin words have J. Until the 19th century, J was used instead of I in diphthongs, as a replacement for final -ii, or in vowels groups (as in Savoja); this rule was quite strict for official writing. J is also used for rendering words in dialect, where it stands for [j], e.g. Romanesque ajo for standard aglio (garlic).

In Spanish J stands for [x ~ h] (which in some cases developed from the [dʒ] sound, i.e. the same sound that English still represents orthographically by ). In French former dʒ is now pronounced as [ʒ] (as in English measure).

In Portuguese, Turkish, Azeri and Tatar J is always prounced [ʒ].

Hebrew also influenced the English J, which in a few cases is used for [j] in place of the more normal Y. The classic example is Hallelujah which is pronounced the same as Halleluyah. See the Hebrew yod for more details.