General American The three dialects of America * General American, * Eastern American and * Southern American are not equal in importance.
The pronunciation of the Southern States of the United States is not the pronunciation standard of American English. It is peculiar to that part of the country only and has not spread north a "southern accent" is detected at once as characteristic of a locality. Most of the typical American peculiarities of pronunciation are characteristic of both General American and of Eastern American pronunciation.
So, the generally recognizable form of English in the United States is termed General American. As General American is the literary standard of American English, it is used by radio announcers and by most of those who speak over the radio; also it is used in motion pictures and in television.
There are the following characteristics of General American. Consonants 1.Rhoticism, that is, the preservation of preconsonantal [r] and usually lack of intrusive [r]. 2. In GA there is voicing of post-stress intervocalic [t]. 3. There exists a "darker" (more velar)  than is typical of British RP. 4. [h] is voiced in intervocalic position: lost initially in unstressed or weak forms within a phrase. 5. [S] is vocalized in "version", "Asia" and so on.
In present day English there are some changes allophonic rather than phonemic that are characteristic of both British and American English. For instance, a glottal stop [?] is characteristic of many dialects of contemporary English. The sound itself, or the pervasiveness of it, is apparently a recent phenomenon in English. Yet in no dialect is [?] a phoneme; in most dialects it is simply an allophone of [t] (in some dialects it is also an allophone of other stops, particularly in final position). The system itself has neither added nor lost a phoneme
For example: we frequently hear [h] in "forehead", [p] in "clapboard" and [t] in "often". American "schedule" with [sk] arose because the sch-combination in words "scheme", "school", "schooner" and "scherzo" is pronounced [sk], whereas the [S] pronunciation of [sch] is for the most part confined to rarer or foreign words like "schuss", "schmaltz", "Schumann" and so on.
Occasionally, spelling pronunciation takes over entire patterns. Many younger speakers in the United States regularly have  in "calm", "palm", "psalm", "balm", and "alms'. This spelling pronunciation has not yet spread to "talk" and "chalk" or "folk" and "yolk", but could do so in the future.
The greatest amount of activity has centered around the voiceless stop [t]. American English now voices this sound when it occurs intervocallically and after the major stress of a word. For most younger speakers such pairs as "betting/bedding", "citing/siding", "title/tidal" and "matter/madder" are total homophones. There is evidence that voicing in this position will spread to the other voiceless stops as well.
There are confusions of the graphemes "g" and "q", "k". There are such spelling errors as "conseguently", ''signifigant", "historigal" and so on. Certainly, intervocalic [k] seems to be moving towards [g] when under minimal stress, though the appearance of such pairs as "picky/piggy" or "locker/lager" is not yet obvious.
In American English the glottalization mostly occurs after the major stress (in words like "satin", "rotten", "mitten") and only before [n] and not before other nasals ("atom" and "sitting" have the predictable "voiced" [t]). In many dialects of American English the glottal allophone of [t] also common in final position after both vowels and consonants (put, fight, felt and want). Preconsonantal [r] was lost in the 18 th century in both British and American pronunciation. But since the mid-twentieth century there has been a reintroduction of [r] in this position in many areas in America.
Vowels 1.Americans use [x] in words like "bath", "dance" and "class". 2. Phonetically different vowels in "tot" and "taught" are pronounced alike (but with great variation in the distribution of [L] and [R]). 3. There is clearly diphthongized pronunciation of [QI] and [OI] 4. There is the use of [I] as the final unstressed vowel in words like "cloudy" or "shiny". 5. There is the retention of the vowel in unstressed syllable and wider use of secondary stress than in the case in RP.
Vowels 6. There is a narrow range of pitch variation in "neutral" speech as compared to RP. 7. Vowels are not differentiated by their length (according to D.Jones all American vowels are long). 8. RP [ju:] in "tube", "tune" turned into [u:] GA - "tube" [tu:b], "tune" [tu:n], "stupid" [stu:pid], "due" [du:] (another pronunciation variant – [IV] - "tube" [tIVb], "due" [dIV]). 9. Monophthongization of RP diphthongs: lay [le], gave [gev], rate [ret], low [lL]. 10. "Nasal twang" as in "man". 11. The tertiary or post-tonic stress in GA falls on the Suffixes -oary, -oery, -dry, -mony, -arily, -atire, -on: 'dictio,nary, 'terri,tory, 'monas,tery.
Also we can see that in present day English unstressed vowels have almost universally been reduced to either [q] or [I]. The stressed vowels of English are not absolutely stable today. Both diphthongization of simple vowels and smoothing of former diphthongs are characteristic of a number of American dialects of the South. The most familiar examples are the tendency to diphthongize the (phonetically long ) simple vowel [x] to [xq] and to smooth the diphthong [QI] to [R].
Prosody The major characteristics of American speech noted were nasality and drawling. Many dialects of British English use fewer secondary stresses in polysyllabic words than do most American dialects; compare British "secretary" and "military" with American "secretary" and "military".