This is a thai character with a latin acute accent:
ะ́
ะ́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́́
Here it is in a table. The columns should line up in vi with LC_CTYPE=UTF-8
Mark       UTF-8            UTF-16      CODES
́        | CC 81          | 0301      | COMBINING ACCUTE ACCENT
ะ        | E0 B8 B0       | 0E30      | THAI CHARACTER SARA A
ะ́        | E0 B8 B0 CC 81 | 0E30 0301 | THAI CHARACTER SARA A + COMBINING ACUTE ACCENT
A        | 41             | 0041      | LATIN CAPITAL LETTER A
