Well the easiest way would be right click the toolbar, select customize and change the icons to not show text.

Thanks, Matt. I like having text there, just not that particular text. I find that my eye is looking for something more like "Compose" or MacMail's "New Message." For me, I suspect that "Write" has a near-lifelong (we're talking many decades) cursive connotation. It isn't the biggest of deals, of course, but it's something I would change if I could. Probably something in the source code not user-definable.

Strings are defined in two ways: as entities or properties. While the latter is usually used to build dialog messages, fixed labels for buttons and other UI are mostly defined as entities. Both are either contained in the omni.ja file coming with the installation or can be provided in a language pack. Option #1 has the disadvantage that you'd have to hack the omni.ja file, identify the entity where "Write" is defined (which is newMsgButton.label in messenger.dtd), modify it and update the omni.ja file; option #2 (i.e., creating your own language pack with that string replaced) may require to copy all other strings as well. Either may break with the next update, thus would have to be repeated every 6 weeks.

Thanks. That's really great stuff and I appreciate the details. I am going to dig deeper. Awesome starting point.

You are welcome. Personally, I'm applying a bunch of patches (other than string changes) for each release, and hacking omni.ja works well for me. It's basically an optimized ZIP file and can be unpacked with many common tools. However, it may break when trying to repack it. Thus, unpack it completely into some new temporary folder, make any changes there, rename the original omni.ja and zip the folder contents into the new omni.ja (obviously while Thunderbird is down).

A more permanent option might be to create an extension that adds a "clone" of the "Write" button to the main toolbar, which is identical except for having the desired label and a different id (or maybe the same id would just override it?), then you can swap it from the toolbar's customization dialog. This certainly has a learning curve but you would be done with doing this effort once. Someone experienced in add-on writing would need to help you here (which I'm not).

Anyway, plenty of ways to screw things up.  ;-)

Thanks again. Where exactly is the omni.ja found? Is it necessary to download a Language Pack to get at it? I can't find omni.ja in my iMac's FS. Thanks.

It's located in the installation directory. On Mac OSX, that should be

/Applications/Thunderbird.app/omni.ja

And no, language packs are extensions that can be used to provide alternative strings to the one coming with the installation, that's a different mechanism.

The following seems to be important on Mac: "To open one of these folders (Thunderbird.app), Ctrl-click it and select Show Package Contents. If you simply click it, you will start the application."