Due to the lack of a written corpus, the linguistic developments from Old Norse into Faroese must be deduced through other methods. Some changes can be placed into a relative chronology, for example the loss of [ð] after the effects of skerping (thus deyður and not **deyggjur), though this is not possible for all developments. 
The kvæði provide another clue as to when changes occurred between the settlement of the Faroes and today in the form of rhyming pairs. A look at Regin Smiður, for example, shows that [y] and [i] must have already merged at the time of composition (as liggur and dyggur rhyme), while the development of ve > vø had not yet occurred (as svørð is meant to rhyme with ferð and gerð). 
Attempts to resolve such rhyming discrepancies occur in later redactions of the kvæði, occasionally disrupting our picture of the original form. While in Lyngbye’s version of Regin Smiður the blacksmith says to Sjúrður “Ver vælkomin, Sjúrður / smíðað havi eg svørð / bilar tær ei hugurin / tú verður so víða á ferð” (cf. Lyngbye 1822:78), Hammershaimb’s version reintroduces a rhyming pair by updating the final two lines to “bilar tær ei hugur og hjarta / tú verður til víggja førur” (cf. Hammershaimb 1851:9). 
In some versions of the kvæði, an entire new verse has been added which could not have formed a rhyming pair at the time of the original composition. Such is the case in Nolsøe’s version which opens with the (now rhyming) “Viljið tær nú lýða á/ meðan eg man kvøða / um teir ríku kongarnar / harum vil eg røða” (Old Norse kveða, rǿða) followed by what must be the original opening verse, “Viljið tær nú lýða á / so er mær greint ífrá / Buðlin kong og Gunnar kong / eg kvøði um báðar tá” (cf. FK 1951-63:57) with an old accusative plural (Old Norse þá) no longer found in standard Faroese (nom.- acc. teir). 
This paper examines such rhyming pairs, both old and new, found in Regin Smiður and other kvæði and places the evident sound developments within a relative chronology. Special focus is placed on discrepancies between various versions of the kvæði found in different sources, e.g. Sandoyarbók and Fugloyarbók, to determine which versions preserve older forms of the individual verses. Such sound changes which are discussed include skerping, ve > vø, the loss of [ð], the merger of [i(ː)] and [y(ː)], and the reorganization of vowel and syllable length.