Northumbrian, line 1: 	In nearly (though not quite) all the weak syllables where we would expect <e>, the Northumbrian scribe instead has <ae> or <æ>, which seem to be used interchangeably.  Although I haven't been able to find any documented sound change that would explain this, vowel mergers in weak syllables were ubiquitous from the earliest period of Old English, just as they have continued to be down to the present, so a merger /e, æ/ > /æ/ in this environment in the scribes particular local lect is a reasonably plausible interpretation.  
	Another interesting feature of this line is the use of <g> to represent /j/ in <hergan>.  This seems to suggest that the outcome of the historical sequance /g/ > [ɣ] > [ʝ] > /j/ (conditioned by environment at each step) had already become [j], and merged with historically indenendent /j/, since there is no etymological /g/ in the word /herjan/.  This is my motivation, then, for reading, for instance ['mo:dj[ə]ˌðɑŋk], rather than ['mo:dʝ[ə]ˌðɑŋk], on line two, and so on.  
	Regarding <uard> (presumably [wɑrd]) rather than more standard <weard> [wæɑrd], see the note on line N.5.  

2: 	The <æ> vowel of <maecti> is nonstandard and at first quite puzzling, however, given the scribe's apparent use of <æ> for expected /e/ mentioned above, if we read [mexti], then it would appear that the scribe's lect has not undergone the "Palatal Umlaut" change /[e,eo,i] > i | _h[t,s,þ]#/ which is not beyond the realm of possibility, as this is a relatively late change in Old English.  This interpretation is nicely supported by the spelling <allmectig> in the final line, reflecting the same root.  
	The spelling <end> with an <e> here is somewhat perplexing; it may perhaps represent [ə], but this is conjecture, while contrarily [e] seems to be without a ready explanation, but is after all what the scribe has written.  The <i> in <modgidanc> could more easily be taken to represent an underlying /ə/ realized as a slightly higher vowel under the influence of the preceding palatal [ʝ].  

3: 	The <e> in <werc> seems to suggest that the scribe's lect has not undergone the "Breaking and Retraction" change /i, e, æ > iu, eo, æɑ | _[h,w,r,l]C/ to the full extent implied in West Saxon spelling.  Mercian also did not undergo the full extent of this change, so such incompletion seems quite plausible.  
	The spelling <sue> for expected <sua> (standard <swa>) is puzzling, but may make sense in light of the spelling <end> for expected <ond> in line 2; perhaps all unstressed vowels before resonants > /ə/ in the scribe's lect.  

4:	The <e> of <astelidæ> here could reflect second fronting in the scribe's lect /e/ < /æ/; this is generally considered a Mercian change, but given the close proximity of Mercia, either a wave-like propagation of at least this element of the soundchange into the scribe's region of Northumbria, or simply a feature of the scribe's idiolect conditioned my time spent in Mercia or a Mercian parent or spouse, could be considered probable, while the failure of this change to affect the West Saxon scribe's lect is perfectly expected.  Notably, such an application of second fronting requires the scribe's lect to not have been fully affected by "Breaking and Retraction" /i, e, æ > iu, eo, æɑ | _[h,w,r,l]C/ (since the <l> in this word is actually geminate /ll/ phonemically and phonetically), which meshes nicely with the evident absence of this change in <werc> of line three above.  

5. 	The <a> of <barnum> would appear to show "Northumbrian-Mercian Retraction" /æ > ɑ | _rC/, where the West Saxon Scribe instead shows the effects of "Breaking and Retraction" /i, e, æ > iu, eo, æɑ | _[h,w,r,l]C/; the same correspondence <ar> : <ear> is seen in the first and final lines in Northumbrian <uard>  [wɑrd] versus West Saxon <weard> [wæɑrd].  

6.	This line has two curiosities, both in the word <middungeard>: Firstly, the <u>, as opposed to expected <a>, seems to have no obvious motivation, but we may perhaps be dealing again with a shift of all unstressed short vowels to /ə/ before resonants.  This is circumstantially supported by the alternate spelling <middingard> in the Leningrad Manuscript, which otherwise agrees with this one almost exactly, since this variation could indicate vacillation on how to spell an essentially qualityless vowel.  Secondly, we have very standard <ea> in the second syllable, rather than the <a> that this scribe otherwise seems to uniformly display in etymologically parallel words, as we just discussed in line five.  I am at a loss to provide a linguistic explanation for this; it may simply be an idisyncratic concession to a standard spelling on the part of the scribe.  
	For consolation, we're given one well-known, quintessentially Northumbrian feature, /ɑ > o | _N/ in <mon> versus standard <man> (with a single rather than geminate <n> in compounds).  In fact, this change is still evident in Modern Scots, which is descended from Northumbrian Old English.  

7.	The spelling <tiadæ>, in addition to the <æ> for expected <e> discussed in line one above, also shows <ia> for Late West Saxon <eo> /e:o/; this LWS diphthong can have two sources (and since I haven't been able to find the etymology of teon I'm ignorant of which is actually correct): either early Old English /i:u/, or /e:o/, with Late West Saxon Old English shifting /iu/ > /eo/; /i:u/ > /e:o/.  Hence, if teon represents early Old English /ti:un/, then the Northumbrian spelling here may be explicable as representing a Northumbrian development something like /i:u/ > [i:ə], while if teon has an etymologically original, early Old English /e:o/, then the explanation is more difficult.  Interestingly, Ringe & Taylor (2014), which is generally quite comprehensive, indicates this etymology as favored but uncertain, citing only Late West Saxon examples and the Northumbrian versions of this text, so it may be that there simply are no other attestations of the verb outside of Late West Saxon to confirm or refute such a theory.  

8.	The double <l> spelling of <allmectig> is surprising, since at least in West Saxon, this is generally considered to be a single, ungeminated consonant in this word.  

West Saxon, line 1:	Late West Saxon Old English is much better attested than Northumbrian, so by and large its phonology is better understood, and there are fewer instances in the reading of this text where the spelling of an individual word is problematic or puzzling, so I'l talk a bit more here about open questions or interesting phenomena in Old English Phonology in general.  
	Note that Late West Saxon O.E. (as well as probably all varieties of O.E. other than Northumbrian) palatalizes its velar consonants when adjascent to the non-low front vowels /e/, /i/, and /y/, hence: /k/ > /c/ > /tʃ/ ; /sk/ > /ʃ/ ; /g/ > /ɟ/ > /dʒ/ ; /x/ > /ç/ ; and /ɣ/ > /ʝ/ > /j/.  Although this final change eventually created a merger in these environments of original /ɣ/ into original /j/ in West Saxon, and indeed in most varieties of Old English -- as indeed seems to have happened in the Northumbrian text, given the spelling mentioned above on line one -- the final step may not yet have occurred in this West Saxon scribe's lect, since they still consistently distinguish the two in spelling, so we have transcribed /ʝ/ rather than /j/ for this phone.  
	Another change that is considered fairly general across varieties of Old English is the laxing or centralization of short vowels, so short < a, æ, e, i, o, u, y > represent [ ɐ, æ̽, ɛ, ɪ, ɔ, ʊ, y̽ ], i.e., short lax or slightly centralized vowels, at least as monophthongs, and perhaps also in diphthongs, while by comparison long < a, æ, e, i, o, u, y > represent [ ɑ:, æ:, e:, i:, o:, u:, y: ], i.e., tense long vowels.  This may very plausibly have affected Northumbrian Old English as much (or more) than West Saxon, but I've elected to read the short vowels as laxed in one transcription and unlaxed in the other just for the sake of representing two plausible alternatives.  
	Another feature typical of Old English generally, and especially of West Saxon, which is visible here on the first line, is its unusual array of diphthongs: the <eo> of <heofonrices> ['hɛovʊnˌri:tʃɛs] is a single-syllable diphthong, /eo/, not a two-syllable sequence, /e.o/.  Late West Saxon OE also had /æɑ/, generally spelled <ea>, as well as contrastive long diphthongs /e:o/ and /æ:ɑ/.  Most other varieties also had high diphthongs /iu/ and /i:u/, spelled either <io> or <iu>, and Early West Saxon also had short and long diphthongs usually spelled <ie>, which may have been /ie/ and /i:e/, but the exact phonetic realization of this last pair is less certain.  

3:	The spelling <wurc> here is surprising, presumably representing [wʊrk], rather than the expected [wɛork]; I have no good explanation for this form.  

5.	The spelling <ylda> rather than <ælda>, appears not to be explicable through phonological change, but this word is so rarely attested in Old English (it seems to have been confined to a fairly high register at least as early as Cædmon's time) that it is difficult to even know which form is etymological, or much less how to account for the other.  

7.	The spelling <middangearde>, with a final <e>, seems to unambiguously mark the singular dative form of this noun (phrase), however this is semantically problematic; the dative in Old English is usually used for indirect objects (which would be nonsensical in this case), or in an instrumental sense (also difficult to make sense of), or as the object of many prepositions (but there are no prepositions in the text of which it could be the object).  The text could be emmended by assuming that there should be a preceding <on> in the line, or simply by deleting the <e> to give <middangeard>, but assuming that the text is incorrect (especially since more than one manuscript shows this spelling) should be considered an undesireable last resort.  A subtler change, especially given the highly unsystematic use of wordbreaks in many Old English texts, would be to assume that this should be read actually as two words, <middan gearde>, giving a prepositional phrase rather than a compound noun.  However, this too is not without its problem, since <middan> in this use, with a dative object, would itself usually be preceded by <on>.  
	A very interesting, if extremely speculative, solution might be to suggest that in Cædmon's time, a locative sense of the dative case was still was still in fossilized use with the archaic and high register term <middangeard>.  This is admittedly quite a stretch, but it should be noted that the locative did hsitorically merge into the dative case in the prehistory of the Germanic languages, and that other such fossilized locative uses of the dative are known from other Germanic languages.  Perhaps the strongest argument in favor of this solution is the paucity of sensible alternative which do not require a multiply attested text to be rewritten.