> For those who can't download the app, I took screenshots of all the screens

> with Klingon text:

maj.

Also, contrary to my previous comment, it seems that "the speed of sound" *is* rendered as a single noun {wabDo} - but only where it serves as a unit of measurement, so perhaps a better translation would be "Mach (number)":

wabDo loS, vagh, jav je lengta'

"it travelled at Mach 4, 5, and 6" ('amerI'qa' 'ev chan 'ev X-wa'maH vagh)

wabDo wa' vI' pagh jav

"Mach 1.06" (Bell X-wa' Glennis 'IH)

Elsewhere, the noun-noun construction {wab Do} "the speed of sound" (sic; with a space):

DoDaj vItlh law' wab Do vItlh puS

"its speed was higher than the speed of sound" (Bell X-wa' Glennis 'IH)

QeS 'utlh