Virmaior's answer is good and more defensible, but addressing LeBerg's comment that it seems like a superficial explanation, here is a potential deeper explanation. The following applies to some philosophers, especially those working on esoteric philosophy, and although it may not explain the intention of Adorno et al., it may set the stage for conventions they followed.
Language affects the way we think, and different languages can come with different worldviews. In esoteric wisdom traditions, alphabets are thought to convey layers of meaning. Hebrew is a good example of this even on the surface: each letter represents a sound, a number, and a symbol like a heiroglyphic. Arabic and Greek alphabets - which are both sometimes used in the way you describe - share common roots with Hebrew in the Phoenician alphabet. Esoteric philosophers take this importance of the alphabet further, as in the various forms of Kabbalah where the shape and arrangement of letters and the sounds they convey all contribute to subtle but important meaning in our communications.
With that background in mind, discussing a topic in English versus Hebrew will come with different contexts and worldviews, with different options on how to convey ideas. Further, discussing using the Hebrew alphabet versus transliterated Hebrew may come with yet another context and worldview with different options on how to convey ideas. This is recognized in religious institutions: special languages are still used to convey religious ideas and statements, and though transliteration can be used to make the language accessible to those untrained in it, the original alphabet is usually included side-by-side with transliteration and translation, or the original alphabet is used for words of particular importance.
That latter case is a pattern continued into some philosophic traditions, where native language is used for most descriptions but a revered special language (including its alphabet) is used for important concepts or words. It is as if the meaning of those spcial words can only be conveyed, or at least is best conveyed, with the language, alphabet, and worldview it was first recognized in.