The names of the letters are for the most part direct descendants, via French, of the Latin (and Etruscan) names. (See Latin alphabet: Origins.)
The regular phonological developments (in rough chronological order) are:
In general, these devices are not used even where they would serve to alleviate some degree of confusion.
The letters A, E, I, O, and U are considered vowel letters, since (except when silent) they represent vowels, although I and U represent consonants in words such as "onion" and "quail" respectively.
The letter Y sometimes represents a consonant (as in "young") and sometimes a vowel (as in "myth"). Very rarely, W may represent a vowel (as in "cwm", a Welsh loanword).
The remaining letters are considered consonant letters, since when not silent they generally represent consonants.