Month names collection / metastudy

[eggyk]

An interesting example You are not allowed to view links. Register or Login to view. of an author writing a section in Italian(?):

martio, aprili, magio, iunio, julio, augustus, septembri, octobri, nouembri, decembri

However, after december the author switches seemlessly to what seems to be low saxon, in the exact same hand, same ink, same everything. We see 'meye' and 'owest' straight away, with the typical "looks both german and dutch" vibe of low saxon languages. 

But a You are not allowed to view links. Register or Login to view. on in a different hand(?), there is: 
".... blut late in deme achten dage des aprilis - efte des ersten in decembri - dester uet binnen vertich dagen - we des seuendes efte des achten dages des apriles blot let de wirt blint - we up den lesten dach in martio - esfe des viften dages..... "

The manuscript is dated to the 14th century. Does anyone have an idea how this combo of language could have happened?