hiragana - Reading and significance of dakuten with kana for which it normally is not used

Came across these while reading a novel.

How do you read this?

Answer

The letter あ゛doesn't exist indeed in Japanese. But あ゛is rarely used in manga to emphasize the letter あ. The letter ゔ exists. But it is normally written in katakana.

Pronunciation: ゔぁ => va ゔぃ => vi ゔ => v or vu ゔぇ => ve ゔぉ => vo