The original Book of Mormon text uses the verb frighten (13 times) but never the archaic verb fright (or even the noun fright). Here the 1837 edition introduced the dialectal verb fright, which was retained in the LDS text until 1920 and the RLDS text until 1892. According to the Oxford English Dictionary, the verb fright is now rare and is restricted to poetry and dialectal language.
This verb is very old, with citations dating from Old English. On the other hand, the verb frighten is, according to the OED, “a late formation, which has taken the place of the earlier fright ”. The earliest citation under frighten in the OED dates from 1666 (in Samuel Pepys’ diary). The critical text will maintain the use of the verb frighten, the reading of the earliest textual sources for all 13 instances of the word in the Book of Mormon.
Summary: Maintain throughout the text the use of the verb frighten, not the dialectal verb fright that was accidentally introduced into the 1837 edition for Alma 47:29.