English Phonetics/VowelR

====Monothong Replacement====
The English phonetic system has one biggest number of available vowels among the 5 languages currently available for Vocaloid (including monothongs, diphthongs and rhotic vowels).
For replace a vowel, you need to have an idea of which are the closest vowels in terms of sound quality. For this reason, it's a good idea to know which is
 
*Open Vowels:←unrounded [{] [V] [@] [Q] rounded→
**Also known as low vowels, they are pronounced with the mouth open and with tongue in low position in relation from the roof of the mouth. They are characterized by their 'ah' to 'uh' sound quality and they positioned in the bottom of the IPA vowel chart.
*Front unrounded vowels:←open (lax) [{] [e] [I] [i:] close (tense)→
**Also known as bright vowels, they're placed at the left side of the chart and are pronounced with the tongue positioned as far in front possible and with the lips unrounded. It sounds tends to vary from an lax 'eh'-like sound toward a tenser 'ee'-like or y-like sound, as the mouth progressively closes.
*Back rounded vowels:←open (lax) [Q] [O:] [U] [u:] close (tense)→
**Also known as dark vowels, they're placed at the right side of the chart and are pronounced with the tongue positioned as far in front possible and with the lips rounded. It sounds tends to vary from an lax 'oh'-like sound toward a tenser 'oo'-like or w-like sound, as the mouth progressively closes.
*Central vowels:←unstressed [@] [V] stressed→
**Located at the center of the chart, these vowels tends to have an undefined 'uh'-like sound. When a vowel is reduced, it may tend to shift toward a central vowel.
Knowing this is relatively easy known how to replace a phoneme.
:Example: The vowel [e] may be replaced by a [{] in case it's needed a more open pronunciation, or a [I], if it's needed a more closed one
In some instance, some diphthongs and rhotic vowels may be used as replacement of the monothongs, if it's pronunciation is closer to a pure vowel. In the case of the diphthong, this is possible for the mid vowels [eI] and [@U] if their diphthongization isn't too marked:
:Example: The phoneme [eI] tends to sound like a tense [e] in some dialects.
In the case of the R-colored vowels, if the pronunciation is non rhotic, these ones
:Example: The phoneme [Q@] in non-rhotic pronunciation is /ɑ:/, which allows use it as replacement of other open vowels like [V], [Q] and [@].