Another linguist has an even better grasp on the construction of phyrexian phonetics, the reddit user citrus_inferno, who is cited on this gamepedia page: https://mtg.gamepedia.com/Phyrexian_(language)
Here is the romanized phyrexian for 'Basic Land - Swamp'
N"K'XvF'ZXx NxOZ^N^ XxLMxX*T
T^LZ^AxT^N’ N^L'ZNx AxX:L’XxX: <<< my guess
Better than random, but a bit far off from being accurate.
My use of diacritics was more or less just guessing based off other examples. Cirtus_inferno has a rudimentary grasp of diacritic meaning with regard to consonants within the language...I don't quite understand this, so I cannot yet intertextualize this into my translation attempts. Understanding the meaning of the diacritics is certainly key to translation...
"In the study of pronunciation, the most recent theory proposes that the main glyph determines the manner of articulation, while diacritics determine the place of articulation. A further theory suggests that the vowel glyphs are determined by their articulation, rather than being arbitrary. Each vowel is composed of three lines on one side of the staff, one line longer than the other two, sometimes with a "hook" on the long line. The height of the long line indicates closed to openness, the side of the staff indicates front or back vowels, and the presence of a hook indicates roundedness. These can be further modified by diacritics. The same effort produced a partial association of consonant sounds with Phyrexian characters."
Some things are kind apparent / clear after you work with the known information long enough. The syntax tree; prefixes indicating tense; vowels vrs consonants; verbs and conjugation; and various parts of speech.
Proper nouns for instance get a rough phonetic treatment. If I'm not mistaken, 1:1 transliterations are only possible for proper nouns, so it's not possible to crack the language using a cipher. I make this clear in my translation attempts and did my best to base my work off the anglicization of Japanese and the treatment of romaji...detailed in the my reddit posts.
I found it tremendously meaningful, resonant and endearing that they bothered to have the language created in the first place, so I really enjoy the challenge of picking it back up from time to time to try and make more sense of it.