The name "Dejal" is pronouced "DEE-JILL". It is not a French word, so should not be pronounced as "DAY-ZHAL" or other variations.
The name originated from the former initials of the founder of the company, David Sinclair. He used to be David J. Lambert, but both he and his wife changed their surnames to "Sinclair" when they got married, being people who like to make their own conventions. Anyway, back around 1983 he needed a password, so an obvious (if simplistic) choice was something based on his initials. D.J.L. with some vowels to make it pronounceable gave "DeJaL", and thus "Dejal" was created.
Interestingly, it turns out that "dejal" is a word in some other languages. "Dejal" is a Slovene verb, the past participle of the verb "reci", meaning "to say, tell." An example: "He told her that she was beautiful" = "On ji je dejal, da je lepa." ("je dejal" = "told"). Kinda appropriate for a software publisher! It appears that "Dejal" is also a Yugoslavian or Czech name equivalent to "David", which is also fitting given the name of the company founder. If you have any other examples, or corrections, please let us know.