But it seems to me that this is a sound transition rather than an etymology derived from a former language [i.e. Latin]. Because if you try to say almost any of the words with an "ex-" prefix, followed by a vowel, the "h" sound naturally flows in place there, it's almost impossible to say these words (with a written "h" or not) without the support of, at least, a mild "h", esepcially when the vowels take the short pronunication. Exceptions seem to be when the vowel takes the long form, but even then, you can detect and feel a wisp of the "h" there. So my first question is...was the "h" originally there and then dropped from some of these words, or was the "h" added later because it was vocalized? The derivative language (Latin) may have originally dicated the written forms, but somewhere along the way, there was a shift in writing or saying these words which seems to have affected only some of them.

Go to the "ex--" section of the dictionary and compare all the words there (it's only about 4 pages long).