I'm aware of some of the differences in pronunciation between the two, and perhaps this can be covered in greater detail elsewhere, but are there also any other key areas of differences (with perhaps a couple of examples in each)? I'm thinking of intrinsic, linguistic considerations, and not extrinsic factors such as historical origins, etc., unless they shed a light on the former.
Henry Preston Vaughan Nunn, in his Introduction to Ecclesiastical Latin, is helpful in this regard. He sets the stage for the distinctions between Classical and Ecclesiastical Latin by briefly covering the origin of the latter:
The most potent influences in the formation of early Ecclesiastical Latin were (1) the Vernacular Latin of the period, by which the Fathers allowed themselves to be influenced in order that they might be understood by half-educated people, (2) the Old Latin version of the Bible with its many Graecisms and Hebraisms, (3) the Classical Latin as taught in the schools, of which all the Fathers were pupils, or even teachers.
Thus, it's perhaps not surprising that two of the main differences identified between Classical and Ecclesiastical Latin, besides the pronunciation, are grammar and vocabulary.
Many of the innovations of Ecclesiastical Latin, as enumerated by Nunn, can be seen to be either influences from Greek or Vulgar Latin:
- The extended use of prepositions where in Classical Latin a simple case of the noun would have sufficed
- The disappearance of long and elaborate sentences with many dependent clauses
- The disappearance to a great extent of the Oratio Obliqua and the Accusative with Infinitive construction
- The substitution therefor of a new construction imitated from the Greek and introduced by quod, quia, or quoniam.
- The gradual extension of this construction even in clauses where ut would be used in Classical Latin especially in noun clauses.
- The Infinitive used to express purpose or result, as in Greek, and also to express dependent commands
- The Subjunctive is used where it would not be used in Classical Latin and vice versa
- The use of periphrastic forms of verbs, especially forms made up with esse or habere
In the realm of vocabulary, Nunn notes several significant changes in Ecclesiastical Latin:
- The use of a great number of abstract and compound nouns and of nouns denoting an agent and ending in or
- The use of diminutives. The use of words transliterated from Greek.
Donald Fairbairn in fact calls the influence of biblical languages the primary difference between the two varieties:
The main difference between classical and ecclesiastical Latin is that the latter has been influenced to some degree by the Hebrew of the Old Testament and the Greek of the New Testament. A significant number of Greek words and a fair number of Hebrew-style expressions came into the Latin language as Christian writers translated the Scriptures. (Understanding Language, 14)
One example of a Greek loan-word is scandalum, unknown during the Classical period but frequently used in the Vulgate. In English the Greek word it is commonly rendered "stumbling block" or "offense":
nos autem praedicamus Christum crucifixum Iudaeis quidem scandalum gentibus autem stultitiam (1 Co 1:23)
but we preach Christ crucified, a stumbling block to Jews and folly to Gentiles (ESV)
Johannes Tromp, Studia in Veteris Testamenti pseudepigrapha, mentions several others, like propheta and idolum, that came from Greek through Jewish and Christian writings.
Pronunciation, grammar, and vocabulary are seen as the primary distinctions between these two varieties of Latin. Still, the differences are often deemphasized—Fairbairn, for example, calls the distinction between them "somewhat artificial."