I know this question is very old but still relevant.

We now have the ability to provide an "Alternative text after /" to the content attribute (ex: content: '✅' / 'ticked') .

Be sure to add a fallback as a first line in order not to break the compatibility.

Using attr it allows you to pass translations from the HTML element.

<li data-bullet="tick">Lorem ipsum dolor</li>

li:before {
  content: '✅';
  content: '✅' / attr(data-bullet);
}

Sources:

• https://developer.mozilla.org/en-US/docs/Web/CSS/content

• https://developer.mozilla.org/en-US/docs/Web/CSS/attr

• See "Alternative text after /" in the compatibility table: https://developer.mozilla.org/en-US/docs/Web/CSS/content#browser_compatibility