I refer you to:
- I want to add a new language to Google Translate. How do I do that?
- What are Google Translate requirements and criteria to add new language into the list of translated languages?
- How do I add malayalam language to Google translate for translating from english to malayalam?
It’s a straight-out prioritisation game, and there are lots of reasons why Karen would be down the list.
- Not a majority language of a country or state (so you can’t do the lobbying that e.g. Mongolian did)
- Not a majority language of a country or state (so it’s simply not as pressing: Karen speakers with access to computers are likely already going to know Burmese)
- Not a majority language of a country or state (so it is unlikely to have generated an extensive corpus of bilingual text—without which, nothing is possible for Google Translate)
Now, Google can make exceptions, as languages take its fancy; Haitian Creole was one, for example, and an answer indicates that Google made a point of building the necessary bilingual resources. But (a) that’s for Google to build, not you, and (b) Google is going to prioritise by need, and there are a lot of unsupported languages with ten times the speakers: 8 Surprising Languages Not on Google Translate – K International
It’s an unsympathetic answer I know. I think the best you can do is contribute to the online presence of Karen, including getting involved with Drum Publications—so that there is more of a Karen corpus text. And building bilingual corpora is critical: translate things from English, and put them online. Without these, there’s no real point asking Google Translate for anything.
Online Unicode support for even Burmese was extremely late, so there is surely ground to be made up for Burmese-script Karen online.