Accentuated abjad English (ōcćnt̮ōt̖d ōbj̄d óngḷsh)
GNU sed, 168 158 134 105 98 85 byt̖s

ǒr 75 ch̠rs (b̭th ȯncl̮ḍng +1 f̭r th̖ -r fl̠g).

s/([bdfhklt])([aeiou])/\1\u\2/g;y/aeiouAEIOU/̠̖̣̭̮̄́̇̌̑/;s/\B[^ ,a-z]/o&amp;/g


óxpl̠n̄ṭǒn

Wó s̄v́ ō ḅt ȏṡng th̖ čnstr̄ȯnt th̠t ȯnp̑t ȯs ōll ḽẃr-c̄ś.  Wó ȏpc̄ś ōny v̌ẃl f̭lḽẇng ō čnšn̄nt, b̖f̭ŕ čnv́rṭng ōll v̌ẃls ṱ ōcćnts.

#!/bin/sed -rf

s/([bdfhklt])([aeiou])/\1\u\2/g  # upcase vowel following ascender
y/aeiouAEIOU/̠̖̣̭̮̄́̇̌̑/
s/\B[^ ,a-z]/o&amp;/g                # precede with 'o' if needed


Th̖ ǒdd-ḽǒḳng ch̠r̄ct̖rs ōŕ // čnt̠ȯṅng ōll t̖n ōcćnts (/̠̖̣̭̮̄́̇̌̑/).  óxp̄nd̖d ǒȏt ẇth sp̄ćs, th̖y w̌ȏld ḽǒk ḷk̖ / ̄ ́ ̇ ̌ ̑  ̠ ̖ ̣ ̭ ̮ /.

ǒȏtp̑t


přgr̄mṁng p̑zzl̖s ōnd čd̖ ǧlf
th̖ q̑ȯck břwn f̭x j̑mps ǒv́r th̖ l̠zy ḓg
b̖ōȏṭf̮l
ǒń ṙng ṱ ȓl̖ th̖m ōll, ǒń ṙng ṱ f̣nd th̖m, ǒń ṙng ṱ bṙng th̖m ōll ōnd ȯn th̖ d̠rkńss ḅnd th̖m