Microsoft has just pushed Windows 10 Mobile Build 14946 to Insiders in Fast Ring and you can read the full changelog by clicking here. The Build 14946 also has its own set of known issues and you may like to read them before taking the plunge.
Microsoft has fixed the below language pack issue resulting in 0x80188319 error. They have updated the official blog post with the info.
Windows 10 Mobile Build 14946 Known Issues:
If your phone has additional speech packs installed – this build will fail to install on your phone with an 0x80188319 error. This is why we polled Insiders about language pack usage this week. Based on the response, we decided to push forward and send the latest bits. This issue will be fixed in the next build we release. NOTE: Removing speech packs will not correct the issue. Your device will continue to try and download and install the update and fail. It is recommended you move to the Slow ring until this issue is fixed.