The speech of the celestial angels abounds in the vowels A (ah, as in father), and U (as u in rule). One may often determine from the Hebrew vowels in a passage which words belong to the class of celestials and which to the spirituals — i.e., whether they involve good or truth. The former use more frequently the sounds of O and U, for they have a full tone, and also occur oftener in the Third Heaven. (Heaven and Hell 241; True Christian Religion 278;, Spiritual Experiences 5112, 5620, 5787)

237. Angelic language has nothing in common with human language except with a few of our words whose sound reflects some feeling, and in this case not with the words themselves but with their sound, which will be further dealt with later.

The fact that angelic language has nothing in common with human language is evidenced by angels' inability to pronounce a single word of a human language. It has been tried, and they could not. The only things they can utter are the ones that are in complete accord with their own affection. Anything that does not agree offends their very life, since their life is a matter of affection and their language flows from it.

I have been told that the first language of people on our earth shared this nature because it was given them from heaven, and that Hebrew resembles it in some respects.