Differences in Display Between Installed Fonts and Web Fonts

Kazunari Tsuboi

I'm facing a very perplexing issue and would greatly appreciate any insights.

When trying to display Mongolian script on Chrome in Windows 11, I noticed that the Mongolian Vowel Separator (MVS) is being ignored. The font I'm using is Mongolian Baiti MS, and this issue occurs when displaying text on Google Chrome using the font installed on Windows.

Unicode strings are here.
ᠶᠠᠪᠤᠯ᠎ᠠ

U+1836

U+1820

U+182a

U+1824

U+182f

U+180e

U+1820

What puzzles me is that the display changes when I use the exact same font as a web font. For testing, I referenced the TTF file with @font-face and displayed the text using the web font. Despite using the same text string and the same font, the final vowel shape affected by the MVS appears differently.

The desired display result for Mongolian script should look like this.

I have a few questions for the community:

• Has anyone encountered this issue in other languages or scripts?
• Is the difference in behavior between an installed font and the same font used as a web font a bug or expected behavior?
• If I want to report this issue, where would be the appropriate place to do so?

John Hudson

The best place to report this would be
https://github.com/MicrosoftDocs/typography-issues/issues

My initial thought was perhaps different shaping engines, but if you are testing in the same browser that wouldn’t account for the difference.

Kazunari Tsuboi

Thank you very much for your response. I appreciate the guidance and will report this issue at the link you provided. 

Thank you again for your helpful advice.

Kazunari Tsuboi

My initial report was about an issue observed when using Google Chrome. After testing with Firefox, the text displayed correctly. This suggests that the problem is specific to Google Chrome.

FireFox 129.0.2 (64-bit)