This was written by Ben Piscopo, whose website can be found here.

He speaks English with a standard American accent.

Glottal Stops

Standard glottal stops occur with a physical stopping/blocking of sound. For example, “night” becomes nait, or more natively nai‛. Notice how the “t” is stopped? This is very common among words ending with t.

Other endings include:

Diphthongs: “might” becomes mait, or  mai‛

Long vowels:  US – “bought” becomes baat, or baa‛
UK- “bought” becomes boot, or boo‛

Short vowels:  US – “forget” becomes f‛rget, or f‛rge (no apostrophe needed after short vowels)
UK – “forget” becomes get, or ge (no apostrophe needed after short vowels)

Consonants: US – “short” becomes ʃo‛rt, or ʃo‛r‛

*Notice how the apostrophe could follow a vowel or a consonant.

Liaison changes a dark ending

A common expression like “in a minute” is written /i‛n/ /ə/ /minit/, but natively pronounced in-ə mi‛ni. Notice how i‛n becomes in when liaison happens. That means the second syllable is stressed beginning with n, bridging the two syllables. Remember, dark sounds ALWAYS end syllables and never begin syllables.

Other examples:

“stop it”  UK  stop-it, or stop-i    US staap-it, or staap-i
“its a…”   its-ə
” this is a”  ðis-iz-ə

Dots for non-hiatus situations

You should already be aware of the “forgotten” example, which is  f‛rgaa‛·‛n in the US accent. In this case, the apostrophe after gaa creates a glottal stop. The dot separates the glottal stop from the dark sound ‛n. Without the apostrophe and dot it would sound like gaa‛n, which expresses the sound of the word “gone”.

Here are some other examples in the US accent:

“cotton” becomes kaat‛n or kaa‛·‛n.

“apartments” becomes əpaa‛r‛·m‛nts. Without an s it looks like this: əpaa‛r‛·m‛n‛.

“fluently” becomes fluu·i‛n‛·lii.

Using y and w glides

Long and Short Vowels with Dark R

In order to create consistency in S4, the following comparisons show when it is appropriate to use short and long vowels with dark-r.

1) o‛r for US and oo for UK in words using /ɔ/ with dark-r. oo does not exist in the US accent. oo‛r is just an exaggeration of o‛r.
[word] [US] and [UK]
fork, fo‛rk and fook
short, ʃo‛rt and ʃoot
horse, ho‛rs and hoos
sword, so‛rd and sood
or, o‛r and oo
false, faa‛ls and foo‛ls
ball, baa‛l and  boo‛l
jaw, dʒaa and dʒoo
author, aaþ‛r and ooþə
2) ə‛r  or ‛r for US and əə for UK in words using ə with dark-r. əə does not exist in the US accent. əə‛r is just an exaggeration of ə‛r. The dark-r in the US accent is powerful here!
[word] [US] and [UK]
her, h‛r and həə
verb, v‛rb  and vəəb
early, ‛rlii  and əə‛lii
dirty, d‛rdii and dəətii
work, w‛rk and wəək
3) ii‛r for US and ii·ə for UK in words using ii with dark-r. i‛r and iə are just improper pronunciation. They represent accent mistakes.
[word] [US] and [UK]
fear, fii‛r and fii·ə
beer, bii‛r and bii·ə
we’re, wii‛r and wii·ə
4) uu‛r or ‛r for US and uu·ə for UK in words using uu with dark-r. Like #3, u‛r and  are just improper pronunciation. They represent accent mistakes.
[word] [US] and [UK]
sure, ʃuu‛r/ʃ‛r  and ʃuu·ə
cure, kyuu‛r/ky‛r and kyuu·ə
endure,  i‛nduu‛r/i‛nd‛r and  i‛ndyuu·ə
mature, tʃuur/‛r and mətʃuu·ə/tʃəə
5) aa‛r for US and aa for UK in words using long-aa with dark-r. Like #3, a‛r and  are just improper pronunciation. They represent accent mistakes.
[word] [US] and [UK]
bar, baa‛r and baa
dark, daa‛rk and daak
star, staa‛r and staa
farm, faa‛r‛m and faa‛m
bun, ba‛n and ba‛n
bus, bas and bas
truck, trak and trak
* The short a in US pronunciation frequently reduces to ə, as in bəs,  gə‛n, sə‛n, however this is not taught as “standard” in the S4 Native English course series.
6) e‛r for US and ee·ə for UK in ANY words using e with dark-r. Since ee is a bit of a wildcard in S4, the usage is slightly different depending on the accent used. ee‛r represents a deep southern US accent, which is not standard. /eə/ defaults to ee·ə for the UK accent.
[word] [US] and [UK]
hair, he‛r and hee·ə
bear, be‛r and bee·ə
Claire, kle‛r and klee·ə
hand, hee‛nd and hæ‛nd
man, mee‛n and mæ‛n
plan, plee‛n and plæ‛n
jam, dʒee‛m and dʒæ‛m
and, ee‛nd and æ‛nd
 *Many other reductions exist to maintain rhythm.

Using two dark consonants at the end of a word

Although g‛r‛l isn’t the prettiest thing to look at, it is written correctly in the US accent. Words that end with two dark sounds are written this way to maintain the rule of dark consonants. So, the word “turn” looks like t‛r‛n in US and təə‛n in UK. Unfortunately, a clear-n in t‛rn would suggest a different sound than what is actually being pronounced. Although t‛rn looks cleaner, it would cause someone who’s following the rules to say something like “t‛rnə“, which we want to avoid. Clear consonants generally need to be paired with vowels.
Other examples in the US accent:
burn  b‛r‛n
learn  l‛r‛n
perm  p‛r‛m
pearl  p‛r‛l
curl   k‛r‛l
Add schwa before converting dark sounds into clear sounds:
“An apple a day” in dictionary (UK) English would be pronounced
/æ‛n/ /æp‛l/ /ə/ /dei/
But, in a naturally spoken sentence it would be pronounced with liaison.   æn-æpəl-ə dei    Notice how æ‛n becomes æn due to the liaison added to it. When this happens in S4 writing, you must convert the dark sound into a clear sound. æn-æp‛l
The second situation adds schwa (ə) and convert a dark sound into a clear sound. æp‛l becomes æpəl when saying æpəl-ə.
A few more examples:
The people in my hometown.
/ðə/ /piip‛l/ /i‛n/ /mai/ /hou‛mtau‛n/
ðə piipəl-i‛n mai hou‛mtau‛n.
a or ə?  u or ə?
These two sounds, a and u, can be confused with ə quite often in the US accent. The IPA system suggests that /ə/ is never stressed, but in practice this is not 100% true.