Question: Looking through `/usr/share/X11/xkb/symbols/il` under Ubuntu 14.10, there are several Hebrew keyboard layouts defined: “Hebrew”, “Hebrew (lyx)”, “Hebrew (phonetic)”, “Hebrew (Biblical, Tiro)”, and “Hebrew (Biblical, SIL phonetic)”.
This last is the layout I want to enable for my occasional use, but when I go to Settings
»Region & Language and try to add an input source, only the first four options are available to me; see the screenshot below.

How can I enable this keyboard layout?

![screenshot](https://i.stack.imgur.com/f6SjZ.png)

Answer: 
Looking through the files in `/usr/share/X11/xkb/rules/`, I find that the SIL layout is only mentioned in `base.extras.xml` and `evdev.extras.xml`, indicating that some extra effort might be needed to enable this.

Searching for [[xkb rules base.extras enable keyboard](https://www.google.com/#q=xkb+rules+base.extras+enable+keyboard)] turns up mention of an old bug where [*Option to enable extra keyboard layout is lost*](https://bugs.launchpad.net/ubuntu/+source/gnome-control-center/+bug/1009995). And there, I found mention of the invocation needed before layouts listed as “extra” were made available:

```
$ gsettings set org.gnome.desktop.input-sources show-all-sources true

```

This option is also available with Tweak Tool, under Keyboard and Mouse: “Show All Input Sources”.

Once this is done, the “Hebrew (Biblical, SIL phonetic)” keyboard layout becomes selectable.

---

Notes:* The linked-to bug did not affect me; it may have been fixed.
* I needed to log out then log in again before I could switch to the newly-enabled keyboard layout; this might be the case in general when adding keyboard layouts.
I tried this in terminal:

```
$ setxkbmap biblicalSIL
Error loading new keyboard description

```

It indicates that the layout is buggy, which might be the reason why it does not show up in the GUI.

If you install the *ibus-m17n* package (and re-login), you get access to the *Hebrew (kbd (m17n))* layout. I have no idea if that would help you, though. ;)