1768 proposed spelling reform for English
Benjamin Franklin's phonetic alphabet was Benjamin Franklin's proposal for a spelling reform of the English language. The alphabet was based on the Latin alphabet used in English, though with several additional letters that Franklin newly invented.
The alphabet.
Franklin modified the standard English alphabet by omitting the letters c, j, q, w, x, and y, and adding new letters to explicitly represent the open-mid back rounded [ɔ] and unrounded [ʌ] vowels, and the consonants sh [ʃ], ng [ŋ], dh [ð], and th [θ]. It was one of the earlier proposed spelling reforms to the English language. 
The alphabet consisted of 26 letters in the following order:
Other English phonemes are represented as follows:
Vowels.
Franklin's proposed alphabet included seven letters to represent vowels. This set consisted of two new letters, in addition to five letters from the existing English alphabet: "α, e, i, o, u". The first new letter was formed as a ligature of the letters "o" and "α" – – and used to represent a sound that is roughly as transcribed in the International Phonetic Alphabet (IPA). The second new vowel letter, "ɥ", was used to represent or .
Franklin proposed the use of doubled letters to represent what he called long vowels, represented by modern phonemes in IPA thus: long versus short (or, in his notation, versus ), long versus short ("ee" versus "e"), and long for short ("ii" versus "i"). In his examples of writing in the proposed alphabet, Franklin contrasts long and short uses of his letter "e", with the words "mend" and "remain" which, respectively, he spelled "mend" and "remeen". In this system, "ee" is used to represent the sound in "late" and "pale". Likewise, "ii" is used to represent the sound in "degrees", "pleased", and "serene". Sometimes Franklin's correspondences written in the new alphabet represent a long vowel not using a double letter but instead using a letter with a circumflex, ◌̂, as when he represents the sound in "great" and "compared" with "ê" instead of "ee". Franklin's long-short vowel distinctions appear not perfectly identical to the same distinctions in 21st-century English; for example, the only word shown to use is the word "all", but not other words that in modern notation would use . This discrepancy may reflect Franklin's own inconsistencies, but, even more likely, it reflects legitimate differences in the English phonology of his particular time and place.
Franklin does not make a distinction between the modern and phonemes (in words like "goose" versus "foot"), which likely reveals another difference between 18th-century English pronunciation versus modern pronunciation.
Consonants.
Franklin's proposed alphabet included nineteen letters to represent consonants. This set consisted of four new letters, in addition to fifteen letters from the existing English alphabet: "b, d, f, g, h, k, l, m, n, p, r, s" (including the long "s", "ʃ", typical of his era)" t, v, z". New letters were proposed to replace the English digraphs "ng" (= "ŋ"); "sh" (= ); voiced "th" (= ), and voiceless "th" (= ). New consonant digraphs based on these new letters were used to represent the "zh" sound of "measure" (= z) and the affricate sounds of "ch" in "cherry" (= "t") and "j" in "jack" (= "d").
The most influential of Franklin's six new characters appears to have been the letter "eng", , for "ng". It was later incorporated into the IPA. Alexander Gill the Elder used this letter in 1619.