[2] In 1648, Syv entered the Latin school at Roskilde, where he lived at the cloister, holding the office of deputator, an advanced student charged with overseeing the youths.
He seems to have enjoyed teaching music there as is attested in a letter to musicologist Hans Mikkelsen Ravn, thanking him for ten copies of his work Heptachordum Danicum.
Næstved was also the abode of noble woman Anna Gøye who owned one of Denmark's largest libraries, which she gave Peder Syv access.
Together they had three daughters: Ide, Vibeke, and Anna Kirstine, the last of whom married her father's successor as priest in Hellested, Rudolf Moth Bagger.
One documented case in which he undertook the responsibility of his office was when local residents suspected a woman of being possessed by a demon, and accused her neighbor of practicing witchcraft.
They based their work on similar efforts undertaken in Germany, where scholars had organized themselves into language academies to promote the use of German in writing.
[3] In 1663, Syv published the philological treatise Nogle Betenkninger om det Cimbriske Sprog ("Some Thoughts about the Cimbrian Language").
[7] Writing in 1878, Syv's biographer Frederik Winkel Horn describes him as primarily notable for his dedication to the Danish language, though not of outstanding wit.
Horn notes that Syv's dictionary and grammatical writings had been influential in spite of their shortcomings, and that his main importance lay in his collections of proverbs and folksongs.