The letter Y represents an intermediate between the celestial and the spiritual in man, especially in the heavens. Historically, it is closely connected to I and J in English, particularly when it's the initial letter in a word. When it's made with curves, a letter has something of the celestial in it. (Spiritual Experiences 5620, Doctrine Regarding Sacred Scripture 90)

92. The fact that appearances of truth, which are truths clothed, may be seized on from the Word as naked truths, and that when affirmed, they become falsities, may be seen from the many heresies that have existed in the Christian world, and which exist still.

Heresies themselves do not condemn people. An evil life does. And so do affirmations from the Word of the falsities found in any heresy and defended by the reasonings of the natural self.

Everyone, indeed, is born into the religion of his parents, is introduced into it from early childhood, and afterward holds to it, nor is he able to extricate himself from its falsities owing to his dealings in the world.

But to live an evil life, and to affirm falsities to the point that they destroy genuine truth — that is what condemns.

For someone who remains in his religion and believes in God, and in the case of Christianity believes in the Lord, considers the Word holy, and lives in accordance with the Ten Commandments religiously — such a one does not swear to falsities. Consequently, when he hears truths and in some measure perceives their truth, he is able to embrace them and so be extricated from falsities. Not so someone who has affirmed the falsities of his religion, for falsity once affirmed remains and cannot be rooted out. That is because once falsity is affirmed, it is as though the person has sworn to it, especially if it is connected with his self-love and consequent conceit in his own wisdom.

90. Because we are dealing here with the Divinity and holiness of the Word, to what we have already said let me add a relevant narrative account.

I was once sent a little piece of paper from heaven with Hebrew letters on it, but letters written as they were among the ancient people. Today the letters are to some extent formed with straight lines, but among the most ancient peoples they were then rounded and had little hornlike strokes projecting upward. Angels who were with me then said they knew whole meanings from the letters alone, and that they knew the meanings chiefly from the curves of the lines and points of a letter. They then explained what some letters signified separately, and what in combination, saying that he (h), which was added to the names of Abram and Sarai, symbolized infinity and eternity.

The angels explained for me, moreover, the meaning of the Word in Psalms 32:2 from just the letters or syllables alone, the gist of their meaning being that the Lord is merciful also to those who do evil.

[2] They informed me that writing in the third heaven consists of no straight letters, but of letters variously curved, each of which has a meaning, and that the vowel points there serve to indicate the part of the pronunciation which corresponds to affection; that in that heaven they cannot pronounce the vowels i and e, but instead say y or eu; and they do use the vowels a, o, and u, because these vowels have a full sound. They also said they do not pronounce any of the consonants as hard, but as soft. This, they said, is the reason some Hebrew letters have a dot placed within them, to indicate [that they are pronounced as hard, but without a dot] that they are pronounced with a soft sound, saying that hardness in consonants is employed in the spiritual heaven, because there they are concerned with truths, and truth is capable of hardness, unlike the goodness that prompts angels of the celestial kingdom or third heaven.

They said, too, that the Word they have is written with curved letters having symbolic little hornlike projections and points.

It was apparent from this what is meant by the Lord’s saying, “Not one jot or one tittle will pass from the law till all is fulfilled, ” (Matthew 5:18). And, “It is easier for heaven and earth to pass away than for one point of the law to fail” (Luke 16:17).