Disclaimer: I have a doctorate in linguistics. My experiences reading an unfamiliar language in a game may not match anyone else's. :-) (But yes, I totally played Senaar in hard mode. And was extremely entertained by the game's translations of words that we had very, very differently. "Hippie" comes to mind.)
For this, rather than replacing, I could imagine a mouseover/tooltip thing, though since it's already the case that mousing over a Trevosan word has an effect on it, I don't know if that would work (I am not a front-end programmer, not since the Rounded Button Incident). Though that would be tricky in its own right, since you either [rot13 spoiler for morphology] lbh'q unir gb ragre lbhe tybffrf sbe gur -b-/-nv-/-r- sbezf bs rnpu jbeq, be ryfr gur vagresnpr jbhyq evfx tvivat njnl gung gubfr ner sbezf bs n tvira jbeq.
(Speaking of which...there was one point where i ended up finding a document by gnxvat n jbeq V unq--fbeel, ybfg zl abgrf, V guvax vg jnf gur bar V naabgngrq nf "thneqvna (a.)"--naq punatvat vgf ibjry gb nabgure ibjry gb, V guvax, gel gb svaq qbphzragf jvgu "thneqvna (s.)" va gurz, juvpu vg qvq. Ohg V'z cerggl fher gung vg nyfb ghearq hc n qbphzrag jvgu gung jbeq V nyernql unq, juvpu zrnag V pbhyq unir whfg pyvpxrq vg. Juvpu znqr zr guvax, "Jbhyqa'g vg or pbby vs gurer jrer n obahf qbp gung lbh pbhyqa'g trg ol pyvpxvat, bayl ol frnepuvat ba n zbecubybtvpny inevnag bs n jbeq lbh nyernql unq gung qvqa'g nccrne va nalguvat ryfr?" (Ohg gur nafjre gb gung vf cebonoyl obgu "ab vg jbhyqa'g" naq "tb jevgr lbhe bja tnzr". V fubhyq tb jevgr zl bja tnzr. Naljnl, guebjvat gung bhg gurer.))
Long story short: cannot wait for more Jamwitch games. :-)