The 1st phrase of the Lament of Akallabêth (SD/247). It changed little from its original draft, with only the verb unekkū becoming unakkha. Tolkien did not interpret the name Zigûrun in any version of the text, but it can be equated to Sauron from information given elsewhere (SD/250). Tolkien’s gloss was “and so ‽ humbled he-came”, which in more ordinary English might be “and so Sauron he came humbled”.
The subject Zigûrun of the sentence is the subjective form of the name Zigûr. The verb unakkha has the 3rd-person singular masculine inflection u- “he”. In the grammatical rules of Lowdham’s Report, the subject would be emphasized with this syntax (SD/429), so the sense might be more like “and it was Sauron who came humbled”. It could be that the “so” of the English gloss is a representation of this emphasis, and that the initial word kadô is simply the conjugation “and”.
The verb form nakkha is the past tense of nakh- “to come”. Since the majority of the text seems to be in the aorist, this use of the past tense would function as a pluperfect according to the grammatical rules of Lowdham’s Report (SD/439). If so, the sense would be more like “Sauron had come” rather than “Sauron came”. Finally, the position of the adjective zabathân “humbled” is difficult to explain, since Tolkien stated that “adjectives normally preceded nouns” (SD/428). Perhaps it follows because it is used as a predicate of the subjective subject Zigûrun (a construction discussed on SD/429), so that the literal interpretation of the full phrase would be “*and so Sauron [was] humbled, he had come [to Númenor]”. Alternately, zabathân could appear in this abnormal position because it is a participle (verbal adjective).