I use WinReducer to minimize the OS footprint. Deleting features I am not likely to use.So I delete most languages, keyboards, fonts, etc and all MetroApps and reduce the size of the inflated WinSxS folder. My Windows system folder is 2.6 GB and all works perfectly. Used this way of installing Windows since early days ofWindows7 so I have some experience.
Sometimes I go too far and delete something that I might use in the future so I just make another WinReducer ISO with the feature intact. In this case I suspected a Thai font was missing so I included Leelawadee in a new ISO image. The Thai font Leelawadee is included in the standard Windows 10 ISO. After the new install worked I copied Leelawadee.ttf from the Font directory and put on another PC and installed it (right click on the font file/Install) and now the language bar display looks as expected on all our six PC's.