You can make speech balloon as you like.

WordPress の記事内で簡単に吹き出し会話を使えるプラグインです。AMPページでも通常ページと同じように吹き出し会話を使えます。 This is a plugin that makes it easy to use balloon conversation with WordPress. It's also available for AMP page.

Support for Block editor(Gutenberg) & Classic Editor.You will easy to add speech balloon in your post.