Tremendous Text toolbar technical terminology

Summary:

After seeing inkscape#1639 (closed), I realized that the terminology used in the Text toolbar is, at very least, inaccurate.

1. Spacing between baselines (X) should read either Leading or Linespacing.

• I imagine the logic was to simplify for non-professionals, but then why was the term "baseline" used?

2. Spacing between letters (px) should read Letterspacing or Tracking.

• If insisted upon, Kerning could be used but kerning is specifically beween two letters and not a line/block of type. But in today's digital world, like the term "font", "kerning" has also been subverted

3. Spacing between words (px) should read Word-spacing
4. Horizontal kerning doesn't even exist! This option should read Horizontal offset as that is what it does
5. Vertical kerning also is a made-up term. This option, like No. 4, shoud read Vertical offset
6. Jumping to the last icon (although I can't test it myself) probably should read only Text direction

Not wanting to create a triaging issue here but why are the four spacing options in pixels instead of the chosen measurement unit?