Capitalization of Spanish month and day names in syslanguages

Why does SQL Server capitalize month and day names when the language is set to Spanish?

The 'syslanguages' table contains the names as follows:

select langid, name, alias, months, days
from master..syslanguages
where alias in ('English', 'French', 'Spanish')

langid  alias    months                                                                                    days
0       English  January,February,March,April,May,June,July,August,September,October,November,December     Monday,Tuesday,Wednesday,Thursday,Friday,Saturday,Sunday
2       French   janvier,février,mars,avril,mai,juin,juillet,août,septembre,octobre,novembre,décembre      lundi,mardi,mercredi,jeudi,vendredi,samedi,dimanche
5       Spanish开发者_运维百科  Enero,Febrero,Marzo,Abril,Mayo,Junio,Julio,Agosto,Septiembre,Octubre,Noviembre,Diciembre  Lunes,Martes,Miércoles,Jueves,Viernes,Sábado,Domingo

As I understand it, convention is that the names of months and days should be lowercase in Spanish. .NET's behaviour is consistent with this. It doesn't seem that Microsoft is being consistent in this regard across their technology stack.

Any idea for the reason?

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When I was in university Spanish, we capitalized month and day names just like in English. Do you have a citation to suggest that that's incorrect?