Did the opaque Glagolitic letter names, fritu, heru, tsi and sha among them, ever carry a sense in Slavonic?
The first twenty letter names of Glagolitic are ordinary Slavonic words and read together as connected sentences, from azu buky vede, I know letters, through ritsi slovo tvrido, say the word firmly. From fritu onwards the names stop meaning anything recoverable, and the reference literature records them as of uncertain or unknown origin without offering a reading. This is an absence rather than a disagreement: no camps hold rival etymologies for these names, and no investigation has settled whether they are corrupted Slavonic words, reflexes of Greek letter names, or labels that never carried a sense. The same gap stands over the corresponding Cyrillic names, which are the same names.
What would resolve this A systematic etymological study of the full set of Slavic letter names, working from the earliest abecedaria and from the acrostic alphabet poems of the Old Church Slavonic tradition, which arrange the names in verse and may preserve senses the plain lists do not. A demonstration that the names never carried a sense would close the question as firmly as a set of etymologies would.
Slavic historical linguistics; Old Church Slavonic philologyPeter T. Daniels and William Bright (eds.), The World's Writing Systems
What sound did the Glagolitic letter pe write, and is it a letter of the alphabet or a variant of another sign?
The letter is encoded in the Unicode Standard and appears in the abecedaria, the alphabet lists copied out as exercises or inscriptions, more often than in running text. The reference literature reads it as a form of p without establishing what distinguished it from the ordinary letter for that sound, and different sources place different numeral values in this part of the order. Nobody holds a position on the question, which is why the atlas records the letter with no numeral value rather than choosing among the values on offer. It is an unfilled gap and not an argument between camps.
What would resolve this An attestation of the sign in running text, in a context where the word it writes can be identified, would settle the sound. A survey of every surviving Glagolitic abecedary, recording where this sign falls in the order and whether it is ever given a numeral value in the list, would settle whether it was counted as a letter of the alphabet or carried as a variant.
Slavic palaeography; codicology; Old Church Slavonic philologyThe Unicode Consortium, The Unicode Standard