ఒ is short ŏ as in prŏduction. The long form is ఓ as in boat, moan, repose. The two sounds ŏ and ō are similar to o in hŏney and mōre as pronounced in Derbyshire.
These initial forms are found in the dictionary but are laid aside in common use, (Telugu characters) vŏ and (Telugu characters) vō being substituted.
But the consonant V is not pronounced. Thus (Telugu characters) is simple ŏ and (Telugu characters) is ō Accordingly.
(Telugu characters) ŏppu (right) is written (Telugu characters)
ఒకటి ŏcati (one) is written (Telugu characters) or even వకటి
ఒత్తుట ŏttuta (to press) is written (Telugu characters)
ఓగు ōgu (wicked) is written (Telugu characters)
ఓపిక ōpica (patience) is written (Telugu characters)
ఓసీ ōsī (madam) is written (Telugu characters)
The short vowel has two second forms. viz ొ as కొ co గొ ఖొ kho &c.
The six letters ఘ &c. write this separate, as ఘొ. But they usually adopt the second form.
The second form is compound of ె ĕ and ు the sign of u Thus కెు is co, (Telugu characters) గెు go ఖెు kho &c.
The six letters write the ె separately, as usual The long vowel is formed by adding the accent to ొ thus కో cō గో gō ఖో khō &c.
Or by adding ె (dirgham) to the ు thus కెూ cō ఖెూ khō గెూ gō &c.
This compound form is used by all consonants but all of them do not use the simple form.